Welcome to Just Answer. I am here to help you resolve your tax and finance concerns. Please feel free to ask anytime you need extra help.
First, the W-2 and 1099 issue. She can obtain a replacement for all of these from the parties which issued them. The bank entries will not help because they are net of any withholdings. The employers are required to maintain their copies for at least three years so while it may take a bit of time it can happen.
Secondly, taking care of her tax return preparation is something I cannot personally do for her. It is prohibited in my agreement with Just Answer. However, you can take care of this yourself since her situation is simple. Tax Act offers free software and also offers electronic filing. It uses a question and answer mode which, specially in simple situations, makes it much easier than you may think. If you elect to use this service be sure to print and retain a copy for your records. Doing it this way will cost nothing and given her situation will be a far more advantageous approach. The idea that if she earns less than $22,000 she does not have any taxes is erroneous so you will need to address the return requirements.
As to the payment plan idea. Sears will be only too happy to establish a payment plan to retire the credit card debt. The IRS will also do this for any tax debt that may exist but their fees are a bit high. The reality is that you will not know if there is a debt until the returns are done. Here is a link to an IRS page addressing payment arrangements:
Her 2010 returns cannot be prepared until the 2009 returns are done but should also be relatively simple using Tax Act. Their web address is www.taxact.com The software will also permit the preparation of estimated taxes if needed.
Finally, the new employer. The law does not permit a later determination as to whether taxes will be deducted. Employers are mandated by law to withhold from employees. It is not optional. Someone is not being honest with her. She should request that taxes be properly withheld (in writing) as required by the law or begin looking for new employment. It just sounds fishy that they will decide later. How can you withhold on something you have already paid out? This sounds very much like an employer which should be reported to the US Department of Labor.
If you decide to use Tax Act, please let me know. I am familiar with their software (use the professional version in my office) and will happy to assist you with any questions that may arise in the process.