I think there is no harm applying it first. You can always reapply it again. Typically, if you have 1 research paper published in a conference, then your profile will be relatively good. You GPA seems good too. As for GRE, personally, I won't be too concerned about it. What I suggest you to do, is to find and contact a potential supervisor for your MS. If a professor replies you back, then you have a good chance of getting into the school. Basically, if a prof wants you, it is hard for the school to say no.
So, it is important how you write you first inquiry email. I have written a blog post on this:
http://controlgradstudy.blogspot.ca/2013/04/ace-inquiry-email-for-your-potential.html
Furthermore, I have also written a blog post on how to select a supervisor, program and a grad school.
http://controlgradstudy.blogspot.ca/2013/04/selecting-your-program-supervisor-and.html
