How do I fix error 1002 on iPhone 3GS?

My iPhone 3GS has recently stopped working for me. I was texting on it fine one night and I put it down for 5 minutes and when I went to check it, the only thing I could access was my emergency calls. The screen told me to plug my iPhone into iTunes to fix the problem. When I did this however, a message said that the only way I could access the iPhone was to enter my security password so that iTunes could access my data. I could not type in my password because the screen would not come up so I put my phone into recovery mode. After putting it in recovery mode I went to update it with the newest software available. However, once the downloads were finished, I received a notice that said the download failed because of error "1002". I have no idea how to fix this problem and nothing on this site is giving me any advice on how to fix it. I really need my iPhone to work and have no time to go to an Apple store at the moment to get it fixed or replaced. Does anyone know how to fix this problem without downloading new software?