No, DHCP is unlikely the cause of that problem. What you do want to check is your wireless adapter. Go to device manager and right click on your wireless adapter. There should be a advanced tab, you should check the features that are there, heres an example from mine.
Ad Hoc Channel (don't worry about this if you see it, basicly it's just for computer to computer communication with wireless)
Intel Throughput Enhancement (Used to increase the transmit throughput by enabling packet bursting, I set this to enable if you have it)
Mixed mode protection(don't worry about this, just leave it as default)
Power Management (set this to highest if possible, it's for maximum performace)
Preamble Mode (you should worry about this, you can leave it as default to automatic detect long or short, or set it as long for longer range or short for performance)
Preferred Band (this is also important, if your adapter support b/g you should leave it alone)
Roaming Aggressiveness (basic improves your signal to the router, set it to the highest)
Transmit Power (improves coverage, set to highest if possible)
Wireless Mode (leave as default, you adapter should support b/g)
You might not have all these feature, but your adapter should be similar or not. Make sure you update your driver.
For the wireless router you can try to change the channel it operates on, from 1 to 11.