It's a lovely orchid, and as Joshua said, no need to repot it just yet. It's generally a bad idea to disturb an orchid when it's blooming, so wait until the flowers are all finished, and the flower stem is dried. If it stays green, it may put out more flowers for you (if you're lucky). If it's happy, your orchid may keep it's blooms for a month or more.
Orchids do NOT need all their roots to be in, or covered by the medium. When you do re-pot it, choose a slightly bigger pot and use Phalaenopsis bark mix from the garden center. Place the plant slightly slanted so that the cup of leaves drains, and the water never sits in there.