Canon Rebel T3I and Tamron 17-50mm 2.8 non vc is this a good kit lens upgrade or should i stick with the kit?

Should I get the Tamron 17-50 2.8 or stick with the kit lens and then save up 800 dollars for the canon 15-85?? it will take me 8 or 9 months to save up 800 dollars but if I get the tamron ill get it right away? What do you think I like photography of about anything and do you think I need the VC? And should wait to get the canon??