Determining how much to spend is a very personal decision. Take the "2 month’s salary" yardstick with a grain of salt. Instead, select a budget that works for you. Consider financing the ring, as a monthly payment may be more important to you than the total cost of the ring. Remember that your budget will need to cover both the ring setting and the diamond.
For now, there is no right or wrong answer here, but one worth thinking through as you reflect on your finances and educate yourself on that perfect ring.