Congratulations on passing, however that C grade makes it hard to judge how long until you will get in. With an A grade I'd say get all your kit bought and be ready to start as soon as a month away. With a B i'd say you're probably looking at 3-9 months.
Maybe someone in recruitment will come along and give you a rough idea.
Hi mate im going in for infantry on 19th feb. Check with your recruiter he should be able to get you a date regardless of your grade. But if there is more A grade RCTs they will take them first and stick b and c grade on a later course. What infantry regt are you going for.