If you want to keep your original remote, then you can get an IR repeater or IR extender. Radio Shack, Pyramid, etc.
Repeaters simply repeat the IR signal and you still need relatively good line of sight or at least the ability to place the repeaters where they can see each other and one of them can see the device to be controlled.
Extenders take an IR signal, convert it to RF and send the RF to an RF receiver. The RF receiver then converts the RF back to IR and emits the IR. The receiver needs to have line of sight to the components unless it also has wired emitters that can be placed in front of the gear to be controlled or plugged into an 'ir in' jack on the back of the device to be controlled.
If the original remote uses standard IR in the range of 43 kHz to ~100kHz, any RF/IR transceiver will work with it.