Own bike is usually cheaper, but depending on what it is, and the type of riding you're wanting to do when on holiday, hiring may be better.
Hiring is obviously easier, as it means you don't have the faff of packing/unpacking twice, and hauling it through the airports. I always take my own bike, as it's what I'm used to, and it's sufficiently beaten up for me not to worry too much about airport staff abusing it.
For flights, check out Canadian Affair, as they're normally the cheapest, but BA is often not much dearer, and may be the better option depending on airports.
I think I paid about £470 for return flights last year, plus lots for the T2R bike park tour, but you should get basic accomodation for about £250/week. I normally take the equivalent of £500 cash for two weeks, and use the credit card for lift passes/bike repairs.
Time wise, if you go for 1 week, you'll scratch the surface of what there is to ride there. 2 weeks, you might get bored of the bike park if you solely stick to it, but you'd struggle to ride all of the stuff that involves pedalling. Then you've got Pemberton/Squamish.