Where abouts are you in Canada? I'm in BC and can get decent paints here at the local autobody supply.
I'm no expert but you really have to cut the rust out and weld in good metal, otherwise you'll be doing this again in no time. Once that's done, clean it well with wax and grease remover and epoxy. Then filler and sand until its straight. More epoxy, then your paint. I'm sure more knowledgeable guys will have some advice.