You'd better to improve your English first.
Because you have to take an English Exam when you're applying for Seneca.
If your English level is poor,you have to take ESL class in Seneca. The cost of ESL is very high in Seneca.(Around CAD250)
If you are landed immigrant,you can enroll the ESL or TOFEL in other ESL school for CAD20(Full time) or CAD15(part-time) only.