Have a look at the Nikon P5000/5100 and a Fantasea housing (60m) rated. Great little camera on land and very very versatile. Able to take filters etc and wide angles. Amazon seem to offer a good price. Housing can be had from
UNDERWATER HOUSINGS for Digital Cameras - Underwater Cameras - UNDERWATER HOUSINGS for Digital Cameras - Underwater Cameras (mike) for about £160. Housing can also take wide angle wet lens.
Canon G7/9 is more expensive and much bigger. Although G9 I believe does RAW.
Rgds
Pete