As someone who was recently in a similar situation to you, wanting to move on from compacts but on a limited budget, could I suggest that you consider an Olympus in an Olympus housing. I have had a Powershot and a G10, both in Canon housings, the fact that your Canon housing has flooded somehow fails to surprise me, and initially looked at the Nikon D7000 in an Ikalite housing but was put off by the bulk of the thing, both under water and in terms of travelling around, by having to change my strobe to something with a sync chord, and by the price which would have curtailed my diving which seemed rather counterproductive.
In the end I got an Olympus epl-2, although the E-620 was tough competition, in the Olympus housing. I´ve now taken it on twenty dives and can promise you that after the Canon combo you´ve been using you will be astonished by the picture quality and ease of use of the Olympus. The controls are well spaced and clearly marked and at 40 metres, it´s rated maximum, I found they all worked as sweetly as at the surface - if you can use a Canon with cold water gloves on this will feel like heaven. As a further bonus you get to use the cheaper and more reliable fibre optic strobe activation.
Obviously I´m not suggesting that there won´t be occasions when a skilled photographer with a good SLR couldn´t take a technically superior picture, although perhaps that can be balanced against shots the better manoeuvrability of the Oly allows you to take, but the money you didn´t spend could be put towards a second strobe, more dive trips, or both.
New four-thirds, and micro four-thirds, lenses are coming along all the time, I´ll be going for the ZUIKO DIGITAL ED 9-18mm F4.0-5.6 although I suspect your tastes are different, as are ports from Olympus, Zen and Athena - I’ve no idea why Olympus initially claimed the EP-03 was a fixed port casing since this is just straightforwardly untrue. And, since you´ll be buying new, if you have any problems with the kit you´ll be able to sling it back to them¡
Whatever you decide, have a quick look at Olympus first and, completely of topic, if you like the Philippines you´ll love Indonesia. Hope this helps, Roy.