Thinking about a trip like this is really a matter of forward planning.
Accommodation is, of course, the most important consideration.
The cost of treatment is equally important.
Personally, if I were planning this, I'd start by googling hotels in Thailand.
The prices are in Thai Baht and this can be checked by googling a currency converter.
Currently, $1 US = 32 Baht £1 = 52 Baht
Found some 5* hotels here
http://www.bangkok.com/hotels/ Room costs about $81 or £50 a night.
Personally, I would never go to expensive hotels, anywhere. Shop around for location and prices.
Whatever you decide, this is something where the finances must be carefully planned first.
I can say, that in Asian countries, generally, prices are prety low. But I suggest you should be thinking of about £50 or $75 a day to live on.