Heat vent help needed

[ARNGJellybean]

Our house was remodeled before we bought it. I don't think this forum allows me to use the words I would like to describe the contractor. Little things were done so very wrong, but in ways that were un-noticible at the time (i.e. leaving out floor tiles under the fridge and stove, but leaving 2 full boxes of tiles in the garage unused). The most irritating bit of stupidity is the second kitchen heat vent. It used to be on the wall about 3 ft from the corner of the house. The contractor installed a sink/cupboards in that area. Instead of moving the vent at all, he cut the entire bottom of the cupboard out. There's no cover over the vent, no flooring under there- just subflooring and a big hole. And it just happens to be the vent second-closest to the furnace, so it blows a lot of warm air. But it blows at the bottom of my sink, trapping all the warm air unless I leave the cupboards open and show off the ugly hole.

There is no wall-space to move the vent, but if we can turn it 45 degrees it can vent underneath the cupboards and not have the heat trapped. I don't like small spaces and I'm paranoid about spiders, so I'd like it to be the quickest job possible. How hard is it going to be? Is this a DIY project, or will we have to hire somebody? The most we've done with the ducts prior to his is putting them back together after a huge cat fight under the house knocked several pieces off.