You can do HDR with your current camera.
I must have missed seeing that option when reading my D3100 manual.I guess I better reread through it a bit! Lol
Your camera may not support auto bracketing but you can still manually change the exposure value and create HDR images. Even though my cameras have bracketing I often do a 3 exposure shot of -2 , 0 & +2 Ev and combine to create a HDR image.