I agree with the others regarding the collection of info (Audiominds.com is a very good starting point!)

As for the interface: You are currently using your SB-card to record. While you CAN record with it, the device was not actually made to record music in a descent quality.

You mentioned you want to be able to record 2 mics simultaneously. You also already had a look at a Tascam UL122 at $150. This is a very good device. You can however get the UL122 for about $120, the Tascam UL144 will cost you about $150.

Most interfaces nowadays come with a lite-version of top class DAW's an sometimes even with additional software. Tascam ships Cubase 4 LE with the UL-series.