Either your doing it wrong or you connection just really sucks. Are you on Wifi? If so try hardwiring it. If that still doesn't work then the only other option is buying a new router or plugging the ps3 directly into the modem.
Get your Portable ID! Yellow Light of Death 2 year old 60gb and PAID 150 for refurb REFURB lasted 2 months then YLOD again. RECALL? NOPE