Google was indexing my site very slowly, it was noted this week only. So I was looking for the cause. And I found (still not sure this is what worked or not, but you may try this if you feel a slowness in indexing your pages), few issues
1. Site was not updated frequently - my site was not updating regularly, and there was one or two posts daily (Things are changed now 
)
2. The sitemap Tag was commented on the Robots.txt (This happened when I upgraded the BlogEngine)
3. Am using Windows Live Writer to write posts my blog, Ping services was not added to the Live writer, just added them
These are the changes I have made, and after 2 days the issue got solved and now the Google is indexing the website much much faster.