You should file a joint return to include two separate Schedule C's.
In addition, you should file your own 1099-MISC's on you own returns, add then divide the expenses in the most reasonable manner possible.
Doing the above will match your earnings with your 1099-MISC tax forms and will allow you the proper credit with your Social Security earnings records.
However, assuming you are not set up as corporations or have a formal partnership. you should be using TurboTax Self Employed online (or TurboTax Home and Business, cd download), not TurboTax Business
