Wifi on my 4G IPod Touch is very slow/doesn't work

I recently got a new 4G IPod touch to replace my old 2G IPod touch. Both IPods are 8gb. The 4G touch has *very* slow internet connection, while the 2G is really quick. I don't understand why my 4G IPod isn't working that well. I closed down all apps (double clicking the home button and pressing those red circles to close the app) I tried restarting the network settings, I tried deleting apps that seemed laggy, I turned it off (holding down the on/off button for 10 secs) and they all helped, but the effects didn't last very long. I tried unplugging the router and replugging it, nothing. I'm trying not to restore it because have an app that I don't know how to save it's data and i don't want to start back from the beginning. It's called My Horse. Lol I must sound like a freak, but some help would be nice.

Oh yea the old IPod is IOS 4.3 and the 4G one is the latest IOS 5.1.1

edit-It says it has full signal strength, all 4 bars are full on each. I don't understand why it won't work