To fix it, file a 1040X amended return with the appropriate schedules. On the 1040X it says to allow 8-12 weeks for processing. However, at this time (because of the amount of First Time Home Buyer claims) the normal IRS processing time for a 1040X amended return is 12-16 weeks. That's right, 3 to 4 months.
Even by filing the 1040X Amended Return, you are probably going to receive an IRS Underreporter audit for the income not included (or underreported) on the return once the IRS receives your W-2's and 1099's from your employers. Underreporter will send you a CP2000 with a proposed balance due and give you 30 days to respond. If you agree to the proposed assessment you will either need to full pay the balance or get into an installment agreement with the IRS. If you do not agree with the assessment, then you can request an Underreporter reconsideration.
2010 returns are not due until 4/18/2011 almost 2 months from now. While you are supposed to receive your W-2's and 1099's by 1/31/11, it doesn't mean you will. If you are missing W-2's or 1099's you need to contact your employer for them. Also 1099-misc is Non-employee compensation. You should have been keeping track of these payments as well as paying estimated tax payments throughout the year on this compensation. The U.S. tax system is a pay as you go system, you are to pay the tax when the income is earned. You could have filed you return including the amount of the income received without filing the actual 1099-misc with the return.