Advice for wireless network setup

To start off let me explain my house. It is the size of a 3 story townhouse but it actually has 5 floors, they aren't straight up I guess. The walls and floors are concrete so signal seems to be an issue for wifi connectivity. Right now my configuration is as follows:

Fritzbox 7390 - DSL Modem/router/N and G wifi located on 3rd floor
WRT160N - WAP/wired router in basement connected to Fritz box via G wifi and wired to PC and printer as well as a LAN over Power line
LAN over power line - only connected to Xbox at the moment on3rd floor to stream media from PC

I also have an Apple tv 2g on the 5th floor connected via fritz N wifi so I can stream iTunes media to a tv. The connection to the apple tv worked for a few days but now it seems to fail all the time. I tried streaming media to the Xbox as well as a PS3 over wireless but it always times out, that I why I am trying the LAN over power. I also tried sing a E3000 as a WAP but couldn't seem to get DDWRT to cooperate so it isn't being used right now.



Any suggestions on how I can get this house better connected so I can have a reliable network throughout the house without breaking the bank? I am currently stationed in Germany, but am originally from the US so if I were to buy anything it would need to have an English interface, I am already having enough problems with the fritz box since it is only on German.

Any help would be greatly appreciated, especially by my wife.

Thank you in advance.