If your up for starting a quick little project, Hardware Secrets can show you how to build your own IR transmitter for the PC. As the article clip states, if you can use a solder iron, you can build the device.
"Several motherboards have the necessary hardware for the installation of an infrared transmitter/receiver, requiring only the installation of a module containing the infrared sensor. The great problem, however, is that this module is not easily found in the market and, when it is, its price is high. In this tutorial we will show you how to build this module spending barelly nothing. Any user who knows how to use a solder iron can assemble it."