It would work but as said above there would be some serious bottlenecking.
I would look into upgrading your machine perhaps.
If you're thinking upgrading your GPU will give you the best graphics and performance then you're wrong. Your CPU is just as important as your GPU arguably. A 3-core will not be able to handle nearly as much as the r9 290x can handle (bottlenecking). Depending on your specs, you may want to upgrade your CPU before upgrading your GPU.
However it's all dependent on your motherboard. Make sure you check for compaitibilties and do some research before even looking at CPUs and GPUs.
http://pcpartpicker.com/ is the best site to go for upgrading/building PCs. It will tell when your machine/future machine has any incompatibilities with other parts.
Also just a bit of extra information, make the investment for Intel. AMD is horrible.
Ever heard the term you get what you paid for... and when you pay for Intel you get even more because AMD sucks?
I think it's something along those lines... xD
Feel free to post your specs and I (and hopefully/probably others) will advise you what to upgrade your machine with and whether or not it would just be a good investment to build a new machine.
I would look into possibly selling your PC and making a budget for a new build. Based on the GPU it sounds like you'll be wanting to perform graphics intensive programs, software, gaming, etc.
Good luck 🙂