My embedded/internal wireless network card doesn't pick up enough signal for reliable networking/internet usage. However, if I move closer to the source (the window) it works fine. A wifi booster antenna is an expensive solution to my problem, just as an external network adapter with about 1m in cable lenght would be. All solutions however interface with the computer through a usb adapter, is there no solution that interfaces with my ethernet port instead?
You could use a DD-WRT compatible router in client mode - not the cheapest option, but you can use it with multiple devices