It doesn't take very much to run this game good. The suggestions from the guys above are of course great and some way of doing it good. Depends on budget and own pc mechanic skills what you want to spend and how advanced you want to go.
AoC is a poorly written game performance wise, and what I found through four computers the last years is this.
GPU doesn't matter much as long as it has enough memory for your resolution and is specced for DX10 (which all new cards are). Single core cards and single gpu cards (no crossfire or sli) performs best. Some dualcore GPU's actually have less frames per second than their single core counterpart due to AoC not taking advantage of the extra power in a proper way. You should go for a medium range GPU, where the choice between NVidia or AMD would be a personal one, or if some cards is discounted by some amount. So to summarize, single core cards, single cards are better for AoC.
CPU matters much. By changing from a Core 2 Duo E8400 which was clocked to 4,5 Ghz, to a i7 4770K, I doubled my framerate. This is your main spender on your budget. Some Intel processor with 6MB or higher cache. i5 and i7 are the better ones, and look for the "K" versions, meaning you can use auto overclocking in BIOS. On newer motherboards this is actually quite good.
RAM and storage isn't of great importance in Age of Conan, as long as you have enough of it. 8GB RAM and a decent storage device (no green power 5400rpm ****) and you're set. 7200 rpm harddisk (Western digital black and Seagate Barracuda are good) or a 240GB SSD (samsung and intels are good). SSD's improve boot time, launch time of applications and loading times in game.
A proper PSU that should be of the "80 plus gold" certification.
Case, monitor, peripherals as you please and can afford from the rest of budget. I have a Razer Taipan mouse and a Logitech G710+ that I am quite pleased with, though might be out of your price range. Fractal cases are nice and cheap. If you can afford go for a 1920x1200 resolution on the monitor.
You can do fine with a lower spec machine as well. Just get a good CPU and a decent GPU.