Beginner: How To Wire Digital Pins w/ Installed Shield?

This is going to be very basic, and I have to apologize up front for even asking it. I'm not 100% this is the place to post this; however, I am hoping someone can help me out.

I have the Arduino Uno board and just picked up the Seeed Relay Shield. I quickly want to put together a project that will control a lamp with a motion sensor. I have the shield controlling a lamp successfully through programming; however, how the hell do I add in a motion sensor?

I know the shield is not using up all the ports; however, they are all plugged in eliminating the possibility of using the 5V, GND, and D3 port on the Arduino. I know I could solder wires, but I just want to test the thing out. Is there anyway to breadboard this sucker in there? What ports are used at minimum between a Seeed relay shield and an Arduino? I tried breadboarding my Arduino pin 7 to the shields D1 port, but I had no luck.

The seeedstudio relay shield isn't very shieldy, there aren't any pass-thru headers.

Here's a link to more info

The only Arduino I/O pins used are 4, 5, 6, and 7.
The rest get sent up there but for no good reason. I should walk that back a little, there is some on-board XBee support, but Digital 8-13 are in the clear as well as A0-A5.

So far as what to do... You could prop up the relay board from the Arduino headers with some headers in between - specifically between the power header and D0-7. Doing that will leave a gap to access A0-5 and D8-13. That's probably the easiest no-solder solution, but you'll have to get the headers.