Carletons Website states "...We typically receive 160-180 applications for the two year MSW program, and approximately 80 for the one year MSW..." That's about 14 percent(?) chance for the non-BSW applicants.
If it makes you feel better, Carleton also rejected me. I have 30,000 human service hours, 3.4 out of 4.0 GPA for my current master's degree in another field. 3.53 out of 4.0 for my undergrad degree. Also received diversity points for 3 categories. It sucks, but I'm not giving up.
Best of luck to you. I'm holding out for Manitoba. If that falls through, I'm just taking a program in the USA then transferring it to Canada. Something to consider.