You may still need the repeater for long range issues, but given the ultra short range you have now, I’d be concerned there’s something else going on there (interference, bad placement, etc.) and which should be addressed first.
You might try using a parabolic antenna. Ppl usually place their routers in locations based on convenience, typically near a coax/phone port. But that isn’t ideal from a technical perspective. It should be centrally located since the antenna is omni-directional. And it’s better to elevate it (maybe 3-4 ft).
If you must keep it in a corner of the house, consider using a directional antenna to drive the signal where you want/need it most. Placing an omni-directional antenna in a corner radiates much of the signal in useless directions. You can even find cheap, home-made mods to help solve the problem ( http://www.youtube.com/watch?v=L3_KJdJ4FAk