I just built a room on a similar budget. Here's what I can think of off the top of my head for your specific needs...
Digidesign 002 $1000
Presonus FS-8 Preamp $600
Presonus Central Station $500
Room treatment (The most overlooked piece of studio gear) $600-$800
(I got mine from ATS Acoustics. Nice stuff.)
Desk, Rack, misc furniture, speaker stands, etc $500
Headphones, cables, etc. $500 (at least!)
That leaves around $1000 for some decent outboard, like a good all around compressor for vocals, etc. (Used Distressor?)
That doesn't account for additional plug-ins or any additional software, but provided you have decent mics, a decent room, and good material, you could easily make a Pro sounding record with that.
There are cheaper ways to go other than Pro Tools, but if you really want to do it pro, and be compatible with other studios and engineers if you ever want to have someone else mix it, it's the only way to go.
Also keep in mind that no matter how well you plan, you will inevitably spend way more money than you budgeted. So if your budget is really only $5000. Plan to spend $4000.
Good luck!