i had a similar problem 4 yrs ago and ended up going the arthroscopic route. i don't know the technical name for the procedure but the doc shaved down the partial tears in my supraspinatus and labrum and then used a heat probe to tighten up the ligaments.
the procedure went well and i think i'm back at 100%. it took 3 months of physical therapy and about a year until i was back to normal, even though they told me it would be 6 months. today my shoulder feels great and i can lift more than i did before, but i didn't really work out as much before as i do now.
best advice would be to make sure the orthopod that does your surgery has lots of experience with the procedure that you need. a buddy of mine had almost the same problem and had the procedure and it didn't turn out too well for him. he had to go under again. i was lucky in that the orthopod who fixed me was a team physician for a MLB team, took my insurance, and had been one of the pioneers of the surgery...so he claimed.
best of luck.