As an alternative to IR repeaters, you can get an RF capable universal remote. For the ~$150 quoted above, you can get a URC-200 or URC-350 plus its RF base station from Universal Electronics. The 350 is nearly identical to the 200 but adds the ability for individually addressable IR emitters which is of use if you have multiple components that use the same commands (like two Tivos, for example). Universal (Home Theater Master) also has other remotes that are plus or minus the cost of the URC series that you could consider as well.
Radio Shack and Pyramid sell extenders/repeaters that are alot cheaper than $100. One For All (URC-9910) and Radio Shack also have RF capable remotes that will work, but for a few bucks more you can get one of the URC or HTM-MX remotes that are superior.