You need to buy a pre-amp for your mic then plug your pre-amp in your pc (preferably buy a compressor and plu between pre-amp and comp).
And for headphones you could buy a lil mixer that have headphone and main outs.
So you can have both monitors and h-p plus volum control for each.
You can buy a mixer that have a pre-amp, many does for around 100-150$.
If you pay a little more like 250$ you can find a mixer who as pre-amp and effects (reverb,COMP) that can do the job.
So you'll get everything youre lookin for in a single box...