AMD has took last orders for Sparta 65nm based Sempron LE 1250, 2.2GHz single core CPUs and it won't take any orders for it in 2009. The plan is to do the final shipment of this 2.2GHz LE 1250 in late Q2 2009 and to replace it with Sempron LE 1300 at 2.3GHz clock. In the mean time, the company plans to make them coexist.

You can expect the same future for Athlon LE 1640 as this CPU won't be selling directly from AMD as of late Q4 2008 but it will continue to be available to Q2 2009. After this date, Athlon LE 1660 with 2.8GHz clock and Lima 65nm single core takes over. The Athlon LE1660 as well as Sempron LE1300 will be selling trough the whole 2009 and probably even after, but this all depends from the market demand for such CPU.  

AMD won’t make any 45nm single cores as in 2009 AMD believes that you need at least two cores even for ultraportable, netbooks.