The REW signal generator is intended for directly generating test signals while connected to the system being tested rather than saving them to WAV or similar, but you could use REW to generate test signals and capture them using a waveform editor like Audacity by selecting Stereo Mix (or your soundcard's equivalent, e.g. What U Hear on some Creative cards) as the record input.
You can choose the start and stop frequencies and levels for a sweep (log or linear), sounds like Log Sweep is what you need. For help on using the REW signal generator look here:
http://www.hometheatershack.com/room...iggen.html#top or in the REW help.