It is a retail card (bought it from amazon) made by asus and dont know how to find the model number
It's not the ENGT430 DC SL/DI/1GD3 because that one uses passive cooling.
The remaining two models, the ENGT430/DI/1GD3(LP) and the ENGT430/DI/1GD3/MG(LP), use an ASUS proprietary heatsink and fan assembly. Although it does look like a 37mm or 40mm tab mount fan. Cooling ability can be adversely affected if you get a fan that is under spec'd.
You can try contacting ASUS and asking if you can get one from them.