summer schools Bangkok/nanny service

Hello! I plan to spend the July in Bangkok with my 3 kids (1, 5 & 7). We will be staying in the Sukhumvit area (soi 20/30). I was wondering if anyone has had any experience with summer schools there. My girls (5 & 7) will be entering kindergarten & grade 2.
Also I'll need to hire a part-time sitter so I can explore Bangkok while my little one naps. Any recommendations on a nanny service would be much appreciated as well.

Thanks in advance!
Lenore