I am looking for a Digital Audio Interface but I only have around $200 to spend on it right now. What would you say is good for my settup I have thus far?

Mic: MXL 992
Preamp: Tube MP Project Series
Amp: Behringer Ultraacoustic ACX1000
Interface: M-Audio MIDISport 1x1
MIDI: Yamaha PSR-275

Computer: AMD 3.0Ghz Quad-Core, 4GB RAM
Sound Card: Realtek ALC888 (onboard)
OS: Windowns XP sp3
Program Cakewalk Sonar 8.5.3