The plant I know as an umbrella plant doesn't grow that high and is aquatic although still an indoor plant.
I'm guessing that what you have is the one I know as a Parasol plant, (heptapleurum). They can be made to branch out by chopping off the growing tip but I think you have to do that while they're young, worth a try though.
I guess plants have different names in different parts of the country just like other things do.

If it is a Heptapleurum (now called Schefflera), then there is something you can do right now - chop the plant down to the size you want it to be, cutting to just above a leaf or pair of leaves. Now take the tops you've chopped off, make the central stem about 4-6 inches long with 2 or 3 sets of leaves, cut below the last pair of leaves. Now strip the bottom set of leaves off, pop the cuttings in a bottle of water and leave on a windowsill, preferably out of the sun. Give it 4-6 weeks and there should be well grown roots - when there are, pot them up, either in the same pot to make a bushier plant with more than one stem, or individually. And the original plant will just continue to grow from where you chopped it back.