You'll find that, depending on your wireless recievers, 1-3MB/s is actually quite good...
Depending on how old your laptop is and the wireless connection in your desktop, most are 54G which can handle average speeds of around 1.2MB/s (or 12Mb/s). Newer hardware, wireless 300N can reach speeds in excess of 100MB/s (almost 1Gb/s).
If you have 300N wireless in your laptop/desktop you will still need a 300N router in order for it to utilize the packet sizes.
Wired network connection will always be the fastest as it's a direct connection with no obsticles (walls, chairs, book cases etc.).