Its well known that UKIP has significant support across the country, but that is the problem, it is spread out across the country, and not concentrated enough in any one particular area. They will still be lucky if they get a single seat the the GE next year.
It kind of depends how well they do tonight, and how much they can build on that momentum. UKIP does have broad support across the country, but there is no doubt it has its strongholds too, just like the other parties. It tends to do well in the leafy rural villages of the home counties, but also the old industrial northern towns. If they can win, and more importantly be seen to win, I think they might very well pick up some seats in the General election in 2015.