mimish

Hello,
I am 28 years old, have been in good health so far except last February I had a bad stre throat (that I treated with antibiotics) and after a routine test, my urine showed that I had high amount of protein. I did 3 more lab tests including the 24 hour count and the protein was still there. I consulted a nephrologists and he asked me to make another test to see if it was related to the strep I had before, and it turned out positive. He said that it was post-streptococcal glumeronphritis and expected it to disappear after 3 months, so last month I did an extra urine test just to check things out and he said that protein was still there but the tests revealed that my kidney function seems to be fine. He strongly suggested me to go through a kidney biopsy. I unfortunately have no insurance coverage for such procedure and would like to know how much it costs. I also would like to know how bad my case is? Will a biopsy help make a diagnosis? If I am unable to afford it, are there other ways to know what I have?
Waiting for your replies
Thanks