Worlds biggest computer junkyard = eBay!!
You may need to buy more than the fan, but you never know what kind of deal you can find?
But before you do this, if you can get the fan out of the machine, make sure if actually turns. If the liquid was sticky (sugar, sucrose or corn syrup) then the fan may just be glued stuck.
You may actually be able to salvage the fan? You would be surprised at what I have been able to resurrect!
If the fan is bad, you cannot hurt it any more anyway, so no harm in trying. Soak the fan in distilled water for a day, then rise it well with distilled water. Shake as much water as you can out of the fan, hit it with some compressed air, and then let a hair dryer run on the fan for at least 15 minutes. Then let the fan site at least 1-2 days to make sure it is fully dried out.
Re-install and cross your fingers.
Good luck.
JamesO