IF you are wanting to capture it all as one track, not individual tracks you can mix together later, then a simple rig like mine will do the job.
Start with you want a recording / data storage device like, well a computer. I like using my laptop. Quad Core 2.8Ghz, 8GB RAM system. Not super fancy but it does the trick.
Next, you need an audio interface. I am using a Behringer UCA222, although some mixers come with them integrated. I should have gone that way, my bad...
Follow that with a mixer, Going to depend on your amps outs, but figure your guitar amps use balanced TRS cable outputs, and your bass amp uses an XLR, each of you need a mic, Again my setup is good to copy. 12 input mixer with at least 4 XLR ins. And the remainders being stereo 1/4" ins.
Appropriate cabling, amps, mics, mic stands blah blah blah.
Headphone amp with at least 4 outputs, and phones. (you don't want feedback from monitors to your mics do you?)
What is going to vary if you want to do multi track, yet play at the same time, is the mixer and audio interface. For that you would use a multitrack recording device, several good ones have already been mentioned.
If you go the mixer route, the thing you change to go with live performance is that you take the headphone amp and its cabling away, and add a power amp and passive cabs, or just run straight to active powered cabs. I personally like this approach better than multitrack as you tend to record what an audience is likely to hear live, and for my purposes, practice and honing live performance skills it does the trick perfectly. It does however rob you of opportunities to fine tune your sound for final album production. Then again, that might be more of the "Garage Rock" sound you are going for anyway...