8.5 x 11 just cannot fit into an 8 x 10 frame, a few years of working for a framing company and I got this argument a lot.
I'm not sure what kind of printer you are using but if it is a standard printer (like I'm assuming because of the size you are currently printing at) then when you are creating an image on your computer then you need to make it for an 8x10 size so that you can use a slicer to cut the image precisely to what it needs to be.
Me I have a printer that can print up to 16 x 20 can it prints 8 x 10's on it's own, so I don't have that problem. When I first started locally, however, I just utilized a friend and her printing company to make my prints. Try looking for one and strike a good deal.