Hi,
I am also from Bangladesh. Have Passed from Islamic University of Technology (IUT), in 2007 from CIT dept. Nice to meet you.
As far as I know, at Canadian universities convincing a professor is the major and toughest part in the whole graduate admission process. One may get accepted into a Canadian university with lower profile, where as another one with much higher profile may get rejected as he/she has no professor's hold. I know this fact from my own experience.
Anyway, UBC and UWaterloo are very good and reputed schools, generally admits students who are within top 5%-7%(professors don't even respond to mails if not so) at their Under Graduate Universities.
University of Texas at Dallas requires GRE score >= 1200. As you are retaking, hopefully you will be scoring >= 1200. Looking at your other credentials I am having the impression that you should get admit at UT - Dallas, if you can improve your score above their cut off.
I know a guy who have got admitted at University of Massachusetts at Amherst for fall 08 having GRE score 1250 and CGPA 4.72 (out of 5). I don't know this University's cut off or whether any cut off exists.
I am clueless with Iwoa State University.
You have a publication which should add good weight to your profile. With a better GRE score you can aim higher ranked universities like University of Florida - Gainesville, Louisiana State University, University of Houston, Drexel University along with low ranked universities like university of Alabama in Huntsville and university of Arkansas in Fayetteville - which are are safe for you.
Cheers and good luck with your application.