Its AM3+, but gettng one of those leaves you with absolutly no upgrade path and wont even really help you. Although Ryzen processers are better value when building a new system, it may be better for you to just get a new CPU that will work with that motherboard, since windows costs $100 and a CPU change will not require a new licence or reinstall.
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CPU: Intel - Core i3-7350K 4.2GHz Dual-Core Processor ($141.00 @ Amazon)
Total: $141.00
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-09-03 00:25 EDT-0400
This is the best you can do for 150 bucks considering your current setup. You will need to perform a BIOS update before switching the CPUs if you decide to go this route. Although this is a k series CPU, you will not be able to overclock it because your motherboard will not support it.
If you don't think this upgrade is worth it ($140 for about 20% performence upgrade in games as long as your GPU can keep up), consider saving up for better components.