Hi Julie
I did AGW in September 2010 and had a ball. I think the hotels and itinerary have changed slightly but you still start out in San Francisco and end up in Las Vegas, so it'll basically be the same as my experience.
In terms of clothes, the advice is layers all the way. In San Francisco, it can be surprisingly breezy and chilly, so you'll need a fleece etc - especially if you plan to do the boat trip around the bay or use one of your free slots to go over to Alcatraz.
Once you go inland and into the desert, it heats up very quickly so you'll be in shorts/t-shirts during the day, but the temperature plummets in the evenings. Also, if you are doing the Palm Springs aerial tramway excursion, bear in mind that it'll be baking at ground level but freezing cold on top of the mountain. I'd also recommend taking a hat, sun block and mozzy repellent.
As for money, well that's very much a personal thing depending on whether you are a shopper/souvenir buyer. Personally I budget for food, tips etc before I go and set that aside. I'm also tee-total so can't give you an idea about budgeting for wine /beer etc with your meals. You may need to allow for any of the optional excursions that are not pre-bookable because in most cases you have to pay in cash (the exception being the Grand Canyon flights for which you can use cards).
I also took a pre-paid USD card, which can be safer, because if you happen to lose it or have it stolen, the thief has no access to your bank accounts, can't take you overdrawn and can only spend the money you have loaded onto the card before it becomes useless.
Happy to help if you have any other questions
Have a super time
Mandy