What are my rights when my sponsor (wife) abandoned me after 3 months of our arival in Canada?

My 2 kids & myself arived here last June 20, 2007, after 3 months of unstable relationship, i found out she's having relationship & that started my decision to stay away from her. Now she is going after me for child support, i know very well about that law but i dont want to give my wife any cash but rather i can give my kids what ever they want in goods. She has created great destruction on my peace of mind. I got contractual job in the construction industry & i want to move on to stabilize myself for my future & my kids. Can i use what she signed in her contract of sponsorship (3-10years of support) for legal counter purposes? I want to get my kids back but how? My kids are 10&8 y/o & need to be treated well. Im earning $18/hr. Considering my apt. rent of $550 & $506 car loan, would it be enough to support my kids and save some for future loans on housing? Im totally confused and i need legal advice. Thank you and God Bless.