Melo, if you're not going to hire a car and/or cook, then really having a kitchen is sorta redundant as there is no real supermarket in tulamben area (Denpasar/Singharaja the closest).
At $700 a month for accomodation, your best bet is to either approach the dive shop to see if they can help you or go to some place like Paradise where it's about $25 a day for a room, lower if you stay long term.
They have tank and weight rentals with guide inhouse and are about 400m from the wreck. Food is edible but next door to the mimpi and all the other restaurants in the area. Lotsa local stuff in the area as well.
If you have no idea who to use as an ops, I've used Bali International Dive Professionals (BIDP) for all my bali diving since 2000. They can probably help you with accomodation search too.
$700 is this your daily budget

Let me know what daily budget you have including your diving, if you want to see pigmies and the likes, your best to take a guide for sure. Diving up there without a guide is not such a good idea if you want to see the best critters and sites there are some great guides locally and a few great operators up there.
Hehe Graham, I could hear your cash register going KA CHING! For $700 a day, she wouldn't be asking here. And Seraya won't give her too much of a break during high season. It'd be bad business.
$700 would be a month... def not a day!! hahaa
she works in the dive industry after all... 
Hmmm mike, I've seen dive industry guys hit the clubs, get $1000 a night hookers and opps have I said too much about the spending habits of the dive industry? 