For elementary shools, Cherry Chase and Cumberland Schools are highly ranked. In general for Sunnyvale, if you buy on the west side of Central Expressway, you get the better schools. Expect to pay $750,000 - $950,000 for a nice home n one of these neighborhoods.
You may also want to consider Mountain View, which has slightly better schools than Sunnyvale. Expect to pay about $100K more for a similar home. But the neighborhoods are nicer, and some Mountain View homes have Los Altos schools.
Please let me know what your price range is, and I can do some research for you.