Last I was aware, Mike is correct, though I think we allowed theurges to carry twice their perm gnosis. This is separate from Dedicated items. You may have your perm gnosis worth of dedicated items and (for non-theurges) your perm gnosis worth of talens on you; they are not mutually exclusive.
"Ritual Supplies" are usually carried in a bag/backpack; so it falls under the same rule as backpacks, clothing and any other 'bulk' item (bag of M&Ms, jar of dirt, etc). As long as the backpack is Dedicated, it (and it's contents) will cross with you. If you would like to take something out of the backpack (while in the umbra) it costs 1 gnosis per 'item'. small items (marbles, jellybeans, coins, etc) can be taken out 1 'homid fistfull' per gnosis.
Example:
Pebe wants to perform Rite of Cleansing on a group of garou just coming back from killing some wyrm. From his Medicine Bag (backpack/messenger bag-sized that has Rite of Shopping Cart on it), he pulls out a few sprigs of sage, a box of matches, and a small wooden bowl. This costs him 3 Gnosis. He then begins to perform his rite.
I hope this helps.