It's not possible. Your processor uses a totally different socket type from the type used on the i3, i5, i7 processors.
Also only a motherboard for the A505 series laptop will fit in that case.
How to upgrade X205's http://forums.toshiba.com/t5/Satellite-Laptops-all-other/info-for-X205-owners-about-overheating-and-upgrading-hardware/m-p/71871 How to upgrade G55's http://forums.toshiba.com/t5/Qosmio-Laptops/Upgrading-Qosmio-G55-q804/m-p/73304 Coming soon: How to upgrade X305's
Like above guy said, your motherboard's socket will not support the icore series.
However, the 2010 motherboard of the A500/A505s should fit (for the most part)*. Examine the NSKAA motherboard models on sites like eBay, but do so with caution! The socket you would be looking for is socket 989, and make sure that the new icore chip that you buy is compatible.
So: NSKAA socket 989 with say... Havendale/Clarkdale Host Bridge and ... something like HM55 for the south bridge. Do some more research!
*Make sure that the card reader is in the same place on the motherboard... I have seen motherboards that differ than mine in those instances. I do not think anything else is much different.