Unfortunately this router has been known to have this very common issue you speak of; before purchasing another more expensive router might I suggest a few things?
I suggest re-flashing your firmware and make sure you have the latest updates.
If that doesn't work you could try switching to another channel
WiFi Stumbler Scans Local Wi-Fi to Find an Interference-Free Channel
You can also try increasing the power on your laptops wifi adapter.
If it does come down to purchasing something, you can easily find a WRT54G on ebay and flash it with DD-WRT and turning it into a repeater to help boost your signal.
Good luck