There is no solution to this as the download speed of the PSN servers has dropped since more and more people have been getting ps3's and using PSN. I remember when I could get roughly 1mb/sec download speed. Now I am getting around 512-700kb/sec.
If you feel your connection is terribly slow I recommend turning off and unplugging your cable router or phone modem and wait about 10 seconds and plug it back in. This tends to speed things up some times.