Do non-Thunderbolt monitors work with a DVI-D adapter on a Thunderbolt MacBook Pro?
I have the same MBP.  It only has a single displayport/thunderbolt output, which can drive a single monitor.  The only way for it to drive multiple external displays is to use a daisy chained Thunderbolt display, or an adapter that drives multiple displays from a single input (Matrox makes one) or possibly a usb driven adapter.