how much grow in flower stage

my plant needs help how much will it grow, it has about 7weeks left i only want it to grow 6 inches taller cos i dont have the space.

Either tie the branches down, or start topping.
You said 7 weeks left, so can I assume it's been
flowering now for 1 week. If so, It will keep
stretching for another week or two.

does it stop growing upwards altogether and then grow out? at what stage?

The first few weeks of flower they will
stretch up and out. Some strains stretch
more than others...