Hi, yes it is easy to replace the fan, I used a Sunon Miniature Fan 5VDC Square 25 x 25 x 6mm 2.2 CFM 2 Wire Leads, I cut the wires from the connector, leaving plenty of wire to reattach and then soldered the new fan to the connector.

Not sure where you are but there is a company on ebay uk that has these at a good price.

£3.99 each inc shipping, I am sure you will be able to find one and they are a fantastic replacement.