These are the minimum specifications:
- 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
More information can be found here:
You don’t need to use anything else besides UE4, but for more advanced 3D objects and meshes you should use 3DMax, Maya, Blender or any other 3D design program.