I checked out the model you have and its an 80x80x25mm size. There are definitely fans of that size, and of all sorts of speed, CFM etc. Can you pretty buy anyone, just be aware of the connector and header as the ones for sale are 3 pins. Your stock one isn't the greatest so whatever you buy will probably be superior. The fan speed is determined by the PSU so you won't have to worry about that.
That being said, I think you're more than capable in finding a replacement on your own. If there's a local computer store around bring it in and they can recommend you one, if they carry that size of course.