what he said....
(Richards post above).
Def. the way to go.
If you must stick w/two channels for budget, you can still do some AUD/SBD with an edirol UA5. tons of them in the yard sale. nice sounding little box. it acts as a mixer too, so you can pump RCA inputs in as well as XLRs, though you can't mix the delay needed, nor can you separate the channels.
as for mics...
if you want really cheap and wicked quality for the investment, the AT 853u is pretty awesome. sound pro's has them on sale for $150 a pair.
An edirol R9 behind these, good to go. $500 total.
Or...
Studio Projects LSD2 stereo microphone. Its big, ugly...., could be a weapon of mass destruction, but it sounds freakin' great, is quick and easy to setup and would allow you to record in M-S mode for later mix down, eliminating that "get it right on the fly" syndrome.
You could probably find a used one in the $500 range. new they are $700.
go TrailBlazers !