Well that appears to narrow the problem down to the speed of your WiFi network itself. There are three levels of WiFi all based on different versions of the 802.11 standard. The original and slowest is 802.11b which is theoretically capable of 11 Mega Bits per Second data transfer rate while 802.11g can get up to the 50 MegaBit range, and the latest and still not finalize version 802.11n is, again theoretically, capable of up to 150 MegaBits per second. Which of these standards you are using depends on your wireless router and how it is configured and which your laptop is capable of.
Those are, of course, all theoretical maximums and you will seldom, if ever, achieve the maximum. Your actual speed is a function of:
- your network configuration (what devices you have and how they connect to your local network)
- the actual 802.11 hardware and/or software in either computer
- how far your computer is from the router/base station
- the construction of any wall, floors, etc. between your computer and the base station
- the construction of major pieces of furniture in the direct path between your computer and the base station
- interference from neighbor's WiFi signals that are on the same band and channel you are using
- interference from household devices such as cordless telephones and microwave ovens
- even a problematic florescent light in the area
In your situation I would start by:
- taking your laptop into the same room with the base station and see if the transfer rate improves. If it does then you may need to install some sort of a relay device such as an Airport Express to improve the signal in your other room
- get a software utility such as AirRadar or iStumbler to check and see:
- exactly what variety of 802.11 you are running
- what is the effective signal strength at both computers
- if there are any other WiFi networks in your area using the same channel you are
This is still diagnostic and any solution will depend on what you find.
