If my math is correct 500€ = about $725. If computer parts are similarly priced there by the time you are purchasing your computer you should be able to easily purchase a computer that can play it at or near max settings in DX9 and/or possibly high on DX10.
The rig I am using cost me ~$800 about a year ago and is able to play the demo in DX9 at 30-40FPS with max detail settings for DX9 (which is high detail 1200x800). I can't make promises for the prices in the future but you will be able to get some impressive eye candy for that kind of cash.
The one catch is you will need to build the rig yourself. If you have at least a limited understanding of computer hardware you can probably be walked through it but I don't advise it unless you are totally comfortable with it.








