Spend some time exploring your diamond ring options. This time is for looking, seeing what's out there. Setting YOUR standards. Once familiar with the options, establish your budget based on your income, what you feel comfortable spending, and the type and grade of diamond you wish to purchase. And once you've established your budget, don't allow a jeweler to talk you into going drastically over or going drastically under (for a supposedly "great deal") your budget.
Your love cannot be measured by how much money you spend on an engagement ring.
Your engagement ring budget will be based on not only your income, but also your knowledge of diamonds (the "four Cs", certification, shapes), so you'll have a very good idea of both what you can afford and want to spend. If you've done your homework, there shouldn't be any big surprises at the checkout counter.