Well, if you are looking for a cheap solution then i would recommend using any remote you already have
and build a serial receiver.
The receiver has 3 electronic components and a db9 connector and is really easy to make.
However you will have to learn your remote codes through lirc ( which is a paint in the .... for the first time)
Have a look @ lirc.org serial receiver.
I you wanna go this way let me know i can give you some clues.
If you are willing to control your AV gear using ir i would recommend getting usbuirt device.
Rafik