|I'm pretty sure green means sending packets and orange means receiving|
Not normally. The orange light is usually a link light. It should light as soon as both devices at either end of the cable are connected and powered up. It indicates a physical connection. A blinking light there mans there is no physical connection, either the cable is faulty or one of the devices is faulty. This is before any software comes into play.. The green light will flash regardless of which way that data is flowing. Some devices will also have a third light that will indicate what speed you are connected.
PCI Ethernet cards are as cheap as chips. A search on Google will give you many options.