There is a DMZ (Demilitarized Zone) in your router, it allows unrestricted access through your router. Essentially bypassing the firewall and opening all your ports to your PS3.

Set up the DMZ with the IP to your gaming console, PS3. PS2, 360 or whatever. Set your gaming console a static IP, this will keep your router from assigning a new IP and keep the DMZ working for you. That's it, it's easy and you will notice a instant major improvement in your connection.

And, NEVER download wirelessly it's way too slow. If you started a download, then fix your connection redo the download completely (delete what you have and start over again). There is nothing on PSN I haven't been able to download in less than 30 min.

Check your speed at www.speedtest.net. Your speed (wired) should be as fast as your computer, if not you need to set up the DMZ and static IP (wired or otherwise). Whenever possible use your PS3 wired.

Have fun and good gaming.