In SONAR LE before X1 LE, you'll find the audio settings under Options>Audio.
In X1 LE, you'll find the same settings by clicking P (preferences) on the computer keyboard.
ASIO may not work now if you didn't download and install the latest driver updates. M-Audio's drivers are usually pretty good.
If you've ever used the generic ASIO4All driver, you need to remove that from the computer before installing M-Audio's ASIO driver.
MME is the oldest, slowest, least-efficient driver there is. You were using that when you had the USB mic? Sorry if I'm confusing you with someone else.
By the way, what's your operating system and is it a 32-bit or 64-bit OS?
I've never used anything but Cakewalk software, so I can't say whether something else is better or on par with SONAR. It works for me.
My music computer is running Windows XP SP 3 32-bit.
I've read here that SONAR is a little more complex to set up than other DAWs (Digital Audio Workstation) by others who have tried them.
You don't need another sound card; the Fast Track will be your new sound card once everything is sorted out.