WiFi To IPad - Increase The Signal Strength For A Longer Distance?

I use a Linksys WRT54GR router. I recently bought an iPad, and I generally use it in a room that is on the other side of the house and through many walls. When it works, it works nice. But recently, my signal has been weak, and is often dropped. Pages load slowly, or not at all after getting a could not connect to server or whatever message. However, this isnt a huge problem for my laptops when used in this room. I dont believe it is the iPad that is faulty because my iTouch also experiences difficulty sometimes. I need a way to increase the signal strength for a longer distance. I looked at a repeater, but im not quite sure what it is and how to set one up, or where to buy one.