Regular PSA and biopsies

I've had two (2) biopsies in 18 months. The 1st was the result of a regular PSA of 5.25 and yielded no cancer being detected. The second PSA was 6.24 and only 8 specimens were taken because I could not tolerate the procedure and became too sore to continue during the operation; however, those specimens also did not show any cancer. The last biopsy was in October/07. I've had two PSA's since - 25.28 and a 36.24 and showed no infections or enlargement of the prostate. Just recieved another PSA at 7.7 with a % free at 21%. My urologist suggest another biopsy. What r your thoughts on my situation.