Depending on the balance in your capital account, you may be able to write-off the additional investment as a capital loss when you dispose of of (close) the partnership.
As you described the transaction, it would not have been a "loan" since there isn't any expectation of being repaid by a "closed business".
The $7000 would be a capital contribution to the LLC and would raise your cost basis in the investment. Once the business is closed - no assets, no activities - you would receive a Final K-1.
Report the Final K-1 on your tax return, and indicate you "disposed" of your interest for (presumably) "$0". This will generate a loss in the amount of your remaining capital balance. These entries are made in the Schedule K-1 interview of TurboTax, found under Business Investment and Estate/Trust Income
The capital account contains the following transactions:
+ Investments made by the owner or partner
+ Subsequent profits of the business
- Subsequent losses of the business
- Subsequent draws paid to the owner or partner
= Ending balance in the capital account
