Anybody using a cable booster?

[Footloose301]

Heres the story; We moved into a new house because we got a great deal because the housing has come way down. So we bought a 3700sq ft, 6bdrm, 3.5 bath, 3 car garage house and can you believe it only has 1 (yes, you read correctly) ONE!!! cable jack, and that was downstairs. So I had to run a cable upstairs from the outside of the house into the soffit, into the attic and then split it into the 5 bedrooms upstairs. My room is upstairs and I hooked it to my comcast HD box and the cable is horribly fuzzy so I bought a cable booster for $4.99 on ebay because the cable guy said it would fix the problem. Has anybody else used these? Do I put it before, or after the splitter? Also I'm thinking since my modem runs off the crappy cable connection, that perhaps this booster will strengthen the internet as well....?