Which is the best laptop for Rs.45000?

I am planning to buy a laptop. Maximum budget is Rs.45000. What are the factors i have to look for? Which processor is better? A solo processor of 1.8Ghz or a Dual Core of 1.66 Ghz. I will be rarely playing but may work with multimedia applications like flash and also for playing movies. Will a dual core processor perform much better than the single core processor. What about heating issue? Wil there be slots for adding cards later. Also which is a better brand, especially in terms of value for money and service?