already reported that E series, A series and FX will be the CPU brands for 2012 and that Phenom II and Athlon II brands are slowly but surely dying. You can check it out here
Sempron on the other hand, as a sole representative of single core legacy market, will continue to live at least trough Q1 2012. There is nothing new to show but the Sempron 145 and Sempron 150, both 45W single cores, will continue to live in Q1 2012.
Sempron 150 is faster of two and works at 2.9GHz with 45W TDP while Sempron 145 is 45W single core with 2.8GHz. You should still be able to buy Sempron 140 clocked at 2.7 GHz in Q1 2012.
The current plan is to ship the last Sempron orders in Q4 2011 but the final shipments will be delivered all the way until the end of Q2 2012 or end of June of 2012. It looks like Sempron 140 and 145 will not be shipped after that date but Sempron 150 might continue even in Q3 2012. The reason is simple - you need to have replacement CPUs for single core Sempron customers and these guys won’t want to change the platform to fit inexpensive E series CPU in their environment.
Most Ahtlon II and Phenom II CPUs will also continue to exist in first half of 2012, but after Q4 2011 you won’t be able to place new orders and it will live as long as there is stock at retail / etail stores.