OK. Bummer. Not much PSU there to run a gfx card. But you can use something in the AMD R7-240, Nvidia GT 730/740 range without problem. I was looking at Newegg Canada (it's the only place in Canada I'm familiar with) and found they don't have a big selection of...
Low Profile, Single slot cards that will work well with your limitations. I found these:
http://www.newegg.ca/Product/ProductList.aspx?Submit=ENE&N=100007708%20600286742%20600007855%20600007856%20600007852%20600038363%20600038364%20600473872%20600519936%20600515071&IsNodeId=1&name=GeForce%20GT%20740
I'm going to say that the Diamond R7-240 would probably be the safest bet. It is narrow enough to fit the limited space between slot and case side. It is only a 31W card. It comes with low profile brackets to swap out.
The other cards have a bit too much width even being single slot. The fanless Zotac GT 730 would be another good choice, but I'm afraid it might get too hot closed up in the tiny case next to the side panel with no where for the heat to go.
What processor you have in that PC?
What resolution is your monitor?