Ipod strange Wifi Problem!

Hi Guys, I have a very strange problem with my Ipod: If i try to connect to Internet via Wifi the Ipod simply tells me, that he is unable to join Network xxxxxxxxxx. If i click the Network more often it sometimes connects, but only for like 2 minutes until it disconnects again without error message. I checked password and I'm only like 3 meters away from my router. I restarted my Ipod aswell as my Router, tried to change language to english from my native language. My Router does not filter Mac Adresses. My Ipod is on version 5.0.1 and always tells me that connection range is very good, but it simply is not able to join. Now about the strange things: I do have 2 Ipod's and both had a good working internet connection until last week. From then on both Ipods had this problem. And: IF I go to different spots in my house, I can join the Wifi Network, but it disconnects when I go away from them again, even though my ipod tells me that signal strength is always good. The Spots with working internet seem to be unaffected by distance to my router.

Thanks for your help.