should be pretty easy
i have a similar set up and distance and have just plugged one g AP (access point)into my primary network then another AP into the secondary network and run them in bridge mode, works fine with the std antennae but it is clear LOS (line of sight) with no trees or buildings and the AP's are sitting in windows in view of each other
(when you setup 1st time leave the encryption off till you get the connection sussed - it makes life a little eaiser!)
if they dont work properly out of the box you could try some slightly higher gain directional antennae say 6-8dB that should help. avoid amplifiers for a shorter distance like that, they probably cause more problems than anything else.
i guess the linksys ap's would be a good option as the range is good or you can unscrew the antenna and put a bigger one on if you need or u can get some elcheapo ones from Dick smiths (no groaning please!

)
heres a link to a co. who have a few options at guud prices
(click here for link to ap's) and some antenna options too
hope this is helpful
lata
mos