I've had good luck with this, and it seems to be readily available at brick-and-mortar stores. Even if it's too late for you now, it might be a good idea to pick one up for the future. I don't think it's currently Linux-compatible though.

Yeah, it is. Sorry. There seems to be some talk that newer versions are not the same as old versions that did work. Anyway, YMMV, but it seems to work pretty well for me under Windows, and the usbserial module for Linux works with at least some of them.