Hi livewire. I can't specifically answer your question but I would say you need to do 2 things before splashing out.
1.Where is the router and could anything be interfering with the signal, such as a video sender or wireless telephone etc.
2. What receiver are you using? USB dongle, wireless adaptor etc. I had a problem with my DLink router with range on both of these but with a laptop the signal is 5 bars everywhere in the house.