If you are planning to visit, I would wait until you can go for 2 weeks...never done a weeks visit & I wouldn't fancy it + by the time you get there it is more or less time to come back.
The only thing I would say, like Joe previously said is that those are the Easter holidays, so airfares are going to be expensive.
I'd look to get out of Manila after a few days, personally, I don't like it very much. I don't think you get a real sense of the Philippines, until you leave there. Of course this is just my opinion & it all depends what you both like doing.
