ATI Radeon HD 2600 Pro fan noise problem

My ATI Radeon HD 2600 Pro video card in my Dell XPS 420 is making a lot of noise due to a noisy cooling fan.  I removed the video card and cleaned the fan and heat sink and then applied a couple of drops of light weight oil to the fan bearing/bushing and then reinstalled the video card.  The fan sounded much better for awhile, but the noise keeps coming and going from time to time.  I would just like to purchase a replacement fan that will fit in the original location on the heat sink.  The fan on my video card was manufactured by Young Lin Tech Co. in Taiwan model# DFC601012L and is a DC 12V 1.6W 55mm frame-less fan, which is attached with 3 screws to the heat sink (2-wire power connection).  Does any one know of a source for this fan or perhaps another fan that will work with my video card? 

I've read on other forums that some people think the cooling fans on these cards my not be necessary if the computer has adequate air flow through the computer.  Anyone here have an opinion of this?  Thanks.