Ethiopian troops are reported to be as far as 140 miles inside Somalia. The Counterterrorism Blog has details.

Note the arrows I have added to the map. The blog reports suggest that the Ethiopians are moving to secure the two major roads in the region, which end up in Mogadishu. Their military has significant combat experience, and is not adverse to using mercenaries. Depending on logistics, and the blog suggests that Central Command may be their support for that aspect of the movement, they could move towards the capital in a matter of days if not hours.