Apple now has replacement feet for these models.
Instructions here:
http://support.apple.com/kb/HT5236
If you are still under Applecare, you are likely covered for the costs.
If you are not, the feet can be purchased from Applecare (2 feet per DIY kit, about $15 per kit plus shipping). The Apple kit contains everything you will need (feet, alcohols swabs, superglue) except the screwdriver.
The feet can also be found at other sellers with a google search.
I installed 2 kits on my 13 MBP (all 4 feet). Looks and feels original.