The screenshot shows that your three keywords rank under three on Google too. For some keywords you are under 30 on Google but rank 1 or 2 on yahoo. Keep optimizing the keywords. Keep getting backlinks your site will move upward.

Different algorythms for different search engines. Microsoft and Yahoo now have shared paid search, so I guess their organic rankings might be very similar too.

The general idea is to focus on your google results as 1) they get the majority of the searches and 2) ones you're ranking well in google you're also ranking well in all the other search engines.

Just keep up the work and, like vvsingh said, build more backlinks.