iPod touch cant find wifi?

i recently bought a thirty two gig ipod touch, and ive updated i to 1.1.4 with the software upgrade too. whenever i go go connect to a wifi network, and it automatically finds them, it can never find the one in my house, that my laptop connects to. it has no problems finding my neighbours, or when in the city, finding lots of businesses networks, but never mine. which is really annoying. ive tried resetting the factory settings and all that, but nothing changes. ive also tried manually typing in the network name and password, but nothing works (yes, the spelling was correct). does anyone know anything that may help? the weirdest thing is that my ipod doesnt even recognise my network. also! when i am in the city with loads of networks around, some unprotected, i cant connect to even the unprotected ones? it just says, cannot connect to network. :\
any help would be greatly appreciated.

okaayyy, thank you very much. the problem is that my router is 802.11n. but its an airport extreme, and i think i read something about them being able to do g aswell? is this possible? if so, how would i do this, and how would it affect my internet connection.
thank you!