Did you check out Understory Enterprises? They have both springtails and Oak Leaves. I've never ordered from them but they are in Chatham, Ontario. I couldn't find shipping rates on their website.
I use magnolia leaves as a leaf litter, it works pretty well for keeping substrate of the frogs and it looks pretty nice. If you know someone with a magnolia tree that doesn't go chemical happy, that's an easy way to go.
You might also consider adding live plants to help set up a complete little ecosystem.
I also use Sow Bugs (collected from the wild) as cleaners. Unlike springtails, which get ignored by larger frogs, they tend to get eaten eventually when they wander above ground but that's ok. They aren't an awesome food source on their own, but more variety never hurt.