crissa...if you plug your computer directly into the router, you should improve the speed, but it doesn't sound as if its going to be very much faster.
It sounds as if you are on the very edge of your Exchange area, and therefore have a high loop resistance from the Exchange to you house.
Have you checked whether you can get BT Infinity ? "Fibre to the Cabinet" is being installed in most Telephone Exchange areas and it could be that its available in your area. Look out for a new green cabinet on the side of the road. It will have louvers in it and will probably have a large advertising panel stuck to its front door.
Alternatively, go to the BT website and make enquiries there....put your telephone number in and it will tell if Infinity is available or not. If it isn't yet, it probably will be soon, and you can registers your interest on the site.
If you want any more info, please don't hesitate to ask...I am a ex-BT engineer !