You can make new lantana plants from the one you have. Just break off a stem. A root emerges from a stem of lantana put in a container of water. This root appears 10 to 14 days after you place the stem in water. Once it is rooted, go ahead and plant it.
How and when to prune lantana bushes is often a highly debated topic. One thing that is agreed upon is the fact that depending on the type of lantana, these plants can get quite large. Find pruning info here.