how much money for a week in tokyo

i am travelling to tokyo just after christmas and will spend a week there. i have paid for my flight and hotel. i just want to find out how much i should bring for meals, sightseeing, a few good nights out plus travelling around the city. i will be staying in shinjuku.
all suggestions welcome.

Some basics:
http://www.japan-guide.com/e/e2410.html

for a week i would say maybe 1500-2000 usd..i was there for 2weeks and i used about 3000usd but thats because i dranked alot and bought many things!

Tokyo is an expensive place. If you want to enjoy it to the fullest I'd say you bring more than you expect to spend. There are so many different foods to eat, theme cafe's to visit etc etc. and that is just food & drinks. I think I spend about 1500 euro just for myself in 15 days last summer. Of which I spend only 5 days in hotels and 3 days in very cheap guesthouses. And I have to say I am notorious for being a very low spender :P

I would have at least 10000 yen per day at least. Food alone is probably 6000 a day.

Bring your credit cards just in case.