I will try and help the best that I can.
How are you connecting? Wireless, wired? what is your download and upload speeds?
Strict NAT basically means that your internet connection is being suppressed by something. It can be a number of things... most likely the ports that your PS3 needs to go through to connect to users is restricted somehow. You can open these ports by getting into your router and modifying some settings.
It's pretty easy to do, but you'll need to have some basic computer skills to do it.
Go check out
You must login or register to view this content. and they have tutorials on how to open the ports for the specific router that you have.