Below are the recommended specs for UE4. You are right, your graphics card doesn’t quite meet them. I can’t tell you exactly how it will run, but you should see an improvement with one of the graphics cards you mentioned.
Desktop PC or Mac
Windows 7 64-bit or Mac OS X 10.9.2 or later
Quad-core Intel or AMD processor, 2.5 GHz or faster
NVIDIA GeForce 470 GTX or AMD Radeon 6870 HD series card or higher
8 GB RAM