Two articles I read concerning consumer grade 2.5Gbps networking technology would be worth checking out. This one talks about a 5 port non-managed switch in the $100USD range and this one talks about network cards in the $120USD range.
The key thing about these devices is they run on CAT5e twisted pair cable, not fibre optics, so they can be used in existing modern installations. If you can re-do your cable runs, and install CAT6, you can go up to 10Gbps. These speeds would be very useful in a network file server that you may have built for yourself and is having problems supplying data at the speeds you need.