First: I am not a tax advisor. You should see one.
Second: Check out this answer on Intuit's web site:
To find your 2009 Capital Loss Carryover amount you need to look at your 2009 return schedule D page 2. Line 16 will be your total loss and line 21 should be a max loss of 3,000 for 2009. The difference between line 16 and 21 is the carryover loss to 2010.
So I believe that means your number is +$10k (assuming you had profits as well as losses).
Regarding your second question, see this page, especially:
Refiguring your tax. To refigure your total tax liability for a carryback year, first refigure your adjusted gross income for that year. (On Form 1045, use lines 10 and 11 and the “After carryback” column for the applicable carryback year.) Use your adjusted gross income after applying the NOL deduction to refigure income or deduction items that are based on, or limited to, a percentage of your adjusted gross income. Refigure the following items.
The special allowance for passive activity losses from rental real estate activities.
Taxable social security and tier 1 railroad retirement benefits.
Excludable savings bond interest.
Excludable employer-provided adoption benefits.
The student loan interest deduction.
The tuition and fees deduction.
If more than one of these items apply, refigure them in the order listed above, using your adjusted gross income after applying the NOL deduction and any previous item. (Enter your NOL deduction on Form 1045, line 10. On line 11, using the “After carryback” column, enter your adjusted gross income refigured after applying the NOL deduction and after refiguring any above items.)