Dancing, that's either a very unique approach indeed, or you're leaving out the warm up and cool down. Those could total 3-4miles per session on their own. You also don't mention whether you were cross training or supplementing the running in any way.
My early 5ks for instance were done with perhaps 1 or 2 short runs a week, but I was also playing football on top.
The OP is new into running, and has a low base fitness. Suggesting speed work at this stage I think would risk injury, when an extra 5-10miles a week at easy pace would safely and easily bring the times down.
After that down the line a proper speedwork session could be added.