What are you running now?

If your laptop is not using a longer range wireless, just getting a $20 card for it may make all the difference.

If your laptop is running a longer range card but your router isn't, then changing the router may make the difference.

Try moving the router a bit or changing the direction of the antenna, if the signal is that close, that's all you may need.

I ended up getting an access point and wiring it to the other side of the house when I wanted to extend.