I had Da Vinci almost three years ago and I was fully sexually functional within three weeks after the surgery, I was 46 at the time. I know from what I read here that I was very fortunate. I also recently finished nine weeks of radiation therapy on March 6th 2008 and as of this writing I am still doing okay sexually though I feel like the radiation did take some of the wind out of my sails but so far not a big deal.
I guess my message here is don't give up and continue to work at it you should get some good results. Good luck.