Watch CBSN Live glitches: Congress is demanding answers

Republicans are set to continue hammering the administration over the failures of the website this week, with plans to question several administration officials about the site's rocky rollout and continue demanding information about why it happened.

Marilyn Tavenner, the administrator for the Centers for Medicare & Medicaid Services, will go before the House Ways and Means Committee Tuesday, followed by Health and Human Services Secretary Kathleen Sebelius, who will testify before the House Energy and Commerce Committee the following day. Last week, four contractors who worked on the site testified before the committee as well.

The same day that Sebelius is set to speak before Congress, President Obama will travel to Boston to hold an event on the health care law, a White House official confirmed to CBS News. He is set to speak at Fanueil Hall, the spot where former Gov. Mitt Romney, R-Mass., his opponent in the 2012 election, signed Massachusetts' health care reform into law.

Sebelius' planned Wednesday appearance has done little to satisfy the Republican appetite for information. Rep. Darrell Issa, R-Calif., the chairman of the House Oversight and Government Reform Committee, and Sen. Lamar Alexander, the ranking member of the Senate Health, Education, Labor and Pensions Committee are threatening to issue subpoenas for information they requested Sebelius and HHS if they don't get a response by 5 p.m. Monday.

They information they are seeking, detailed in an Oct. 10 letter, includes questions about the number of people who were able to enroll in insurance through the federal exchange and how many tried, a full documentation of the efforts to test the site, and how much it will fix to cost the problems, among other things.

"We're looking for quick answers so that we can on behalf of the American people straighten out as much as can be straightened out that's above the water -- which is the website -- and the 90 percent that's below the water like an iceberg that are the other problems in Obamacare," said Issa on CBS' "Face the Nation" Sunday.

Issa: Obama "poorly served" by those who rolled out Obamacare
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Issa also said that Sebelius should lose her job if she can't put together the team necessary to fully fix the site.

"The president has been poorly served in the implementation of his own signature legislation. So, if somebody doesn't leave, and if there isn't a real restructuring -- not just a 60-day, somebody come in and try to fix it -- then he's missing the point of Management 101, which is these people are to serve him well, and they haven't," Issa said. "If she cannot reorganize to get the kind of a team in consistently to meet his agenda, then she shouldn't be there."

The flaws have put Democrats in a difficult spot, forced to acknowledge the extensive problems while trying not to overtly criticize members of the administration. Sen. Jeanne Shaheen, D-N.H., for example, called the rollout a "disaster" on "Face the Nation" but also said it's too early to assign blame.

"Right now everybody's goal should be, let's get this working. Let's make sure that people can get the health care they want and need," she said when asked whether she had lost confidence in Sebelius.

Shaheen hasproposed an extension of the enrollment period, currently set to end on March 31, in order to accommodate those who have had trouble using the website. She has 10 Democratic supporters.

Sen. Joe Manchin, D-W.V., did say on ABC's "This Week" he thought Sebelius should stay - but he has also criticized the problems with and called for a one-year delay of the IRS penalty for people who do not purchase insurance.

Many Republicans, for their part, are not holding back. Thirty-three have signed a letter to President Obama calling for Sebelius' resignation. "By calling for the resignation of Secretary Sebelius, you can send a powerful signal that the American people will not be held responsible for her department's failures," the letter said.

During a trip to Phoenix last week, Sebelius said, "The majority of people calling for me to resign I would say are people who I don't work for and do not want this program to work in the first place."

The Republican lines of inquiry also stand to widen this week as users and reporters uncover more problems with the site.  On CNN's "State of the Union" Sunday, House Homeland Intelligence Committee chairman Mike Rogers, R-Mich., said the website does not "not have an overarching solid cyber security plan to prevent the loss of private information."

"The way the system is designed, it is not secure," he said.

The administration announced Tuesday that Jeff Zients, one of President Obama's economic advisers and a former management consultant and CEO, would lead the "tech surge" to fix the website. On Friday, he said the "vast majority of users"should be able to access by the end of November.