If im not mistaken there is a PCI slot on the back. Its just turned sideways? If yes then you have to buy this. http://www.logicsupply.com/products/pci_106_l
I am not sure if it is compatible with your board though.
Another thing you could do is buy a different case: http://www.logicsupply.com/products/2699b
If you really want to keep the voom case, simply buy a risercard thats higher up and mod the case so the risercard sticks out the top of the case and mount the pci card that way. IMO its better to maybe just build a custom case.