my 2.4 certainly ran it comfortably! I would say you shouldn't have any issues with that.
RAM-wise, 1GB is certainly in the comfort zone; you'll notice some performance drops at 512 (as I did) and you'll notice only very little improvement at 2GB (as I do).
Video - I run a 128mb GeForce 6800OC and the performance is more than tolerable. Any card above a GeForce 4200 (except the dreaded FX series) and Radeon 9600 will run it quite decently, any card above GeForce 6600 and Radeon X800 will run it well.
My own system is 3.06GHz, 2GB RAM, GeForce 6800. No real complaints, though GWX harbor traffic is a bit too much for it sometimes. The frame rate is 50s-60s in the open sea, 30s around the bigger convoys (I would mention 12-15 in port, but that is not a problem with my computer - there is a memory leak related to ports in the game). I can run time compression up to 2048, though it's a little choppy at 2048 - but 1024 is smooth.
PS - also a college student at the time of my getting into SHIII, and no, you can definitely afford to have a good SHIII system on a modest budget like mine
