If it's the right girl, she won't care.
How much do you have in savings to spend? I don't recommmend going overboard if you can't afford it. if the woman really loves you the ring won't be a big deal as long as you get something that looks fairly nice and isn't a pawn job.
Honestly I wouldn't go over $2-3K at that if you have that kind of money. do not put this on a credit card. nothing wrong with staying in the $1k-1.5K range and upgrading later on