Nice pictures.. nice house or condo?
i notice your walls are very bare.. u must try to put up some sound insulating material like bookshelves, sofa, big rugs etc. to try to absorb as much of the reflected sound waves as possible.. that will help a bit.
The room is very small, hence the drums, which are by far the loudest instument, will overpower whatever vocals you put out.. throat how to fight with drumset? Its no wonder that u say the vocals can't be heard.. and when u turn up the mic volume, it will just pick up the drum sound more that the vocalist's voice... even facing the mic the opposite way won't help cause the room is so small..
one extreme solution would be to put the drummer in a separate room.. haha.. that will work but then u will have problems communicating with each other.
Think mikemann is right, u should probably do your jamming in a real studio, no offence..
Well, the other solution is to build a sound proof barrier around the drummer. But that will be quite expensive.
edit: you could also try muffling your drumset by sticking a pillow in the bass drum and plastering the skin of the snare with some insulating material. This will lower the overall output of the drumset somewhat.
cheers.