Ah, well that might make it a little difficult.
First off, is your system in a low profile chassis or are you only looking for a cooler that is compatible with your GPU?
If all you need is a silent cooler, I would look into a cooler like the Ac Accelero S1 Rev.2
It will unfortunately only fit into a full height chassis but can easily passively cool your GPU.
If you need a cooler for a low profile chassis you may be out of luck.
You could try something like a Zalman VF700
but I am not sure if it is truly low profile or not.
If the option is available, you may be better off returning your current card and getting a Passively Cooled Version