We got mine in Hong Kong. Selected the stone and had the ring made in 3 days. Went back to Australia and had it appraised at a little more than we paid for it so I was happy.
As far as what you pay for the ring - it all depends on how what you can afford and what her expectations are. He had a fat wallet filled with half my money and I had high expectations.
If you have a lot of money and you get her a little ring, she might wonder how important she is in your life.
Have you asked her what she wants?