Quick answer is that there is an OTP bank next door to the hotel..
Cost are a little tougher because it depends where you are. Andrassy ut is a little pricier than other places. I'm going to find a couple of links to some of my favorite restaurants for you. That will give you some idea.
General rule of thumb, I live in one of the states with a low cost of living, and Budapest is possibly 15% to 25% less depending on the neighborhood; but absolutely not more expensive than my US Home even in the heart of Tourist Hell (Vaci utca and District V in general).
This is a place across the street from the back of the Basilica. Sort of my standard for not quite tourist and not quite local and a short walk from your hotel. Ignore the Euro prices on the menu. The jack them pretty good so they don’t have to reprint their menu so often: http://lugas-etterem.com/etlap/ This will give you a pretty good idea of the cost of eating in town. If you move closer to the river the prices will go up maybe 10%, as you move away from the river and get on the side streets the prices will drop as much as 15%.
There is change in 5, 10, 20, 50, 100 and 200 forint coins. The bills come in 500, 1000, 2000, 5000, 10000, 20000. The 20000 bills are a little tougher to change. I dont know your travel style so i dont how much cash to tell you to pull out. Generally for three meals my significant other and i spend about 10000 forint a day. I will spend another 10000 forint at the wine bar before bed time (wine and pate at Kadarka Wine Bar about a 5 minute walk from your hotel - you will pass my place on the way, so wave!)