Verified answer

http://gotransit.com/publicroot/en/schedule/pubsch...

and yes you can use a credit card

http://gotransit.com/public/en/fares/WHEREHOW.HTM

I think you'll want to take the go transit.

http://www.gotransit.com/publicroot/en/schedule/ls...

You can always buy the tickets for the go bus when you get to york mills station. you should be able to buy with credit card there.