Have overstayed my time in Canada by two years, but now I want to become legal, is there any way to do that by hiring a good lawyer? Please I canno return to my home country because of an abusive husband that I want to escape from, can anyone tell me what are my chances

There is no way of knowing your "chances." You have already broken the law by over staying instead of reapplying.

I would contact Immigration (through an Attorney) before Immigration catches up with you and deports you.

But If I get married to A Canadian Citizen, and then become eligible for Permanent Residency in Canada, would I not be able to stay in Canada until a decision is made on my case?

According to your post, you are already married, and therefore you cannot remarry until you divorce.

Out of reddies, NYcityboy... but good point. Bigamy would probably only make things worse.