The best thing you can do is raise your GPA as much as possible this semester and during your 4th year. Are you hoping to go for a Masters or a PhD? Do you want to apply to schools in the US or in Canada? I don't know much about Canadian admissions, unfortunately. Although a lot of US schools will ask for your psychology GPA separately, getting in with a *GPA below 3.0 is a significant challenge since most programs are looking for a bare minimum of a 3.5. I do believe that a change in major might make the low GPA seem less unfavorable (especially if you continue to do well in Psych), but I'm unsure.
*I am sorry, I have no idea how Canadian GPAs translate into US GPAs. Hopefully someone who knows something about this can respond too, you may also consider asking in the international sub forum.
Additionally, if you're USA-bound, do your absolutely best to get top of the line GRE scores. These can help compensate for poor school performance.
Finally, get some research experience. This does now have to be I/O specific, but working in a psychology lab would be great. Volunteer or try to get a paid lab position over the summer. Work/volunteer in a research lab during your 4th year. Gain as much research experience as you can, hopefully with a publication or some posters if you're lucky. This is one of the best things you can do to bolster your application.
As for the double major, if you think you can take the final bio course without sacrificing your GPA, do it. If not, just focus on maintaining the absolute highest grades you can.