No, the A8-6410 is a weaker APU compared to the A8-7100.
It is not surprising that the ThinkPad T43 does not run the game very well since it was released in 2005. The A8-6410 would be a huge performance boost. To get around 100 FPS in Minecraft I believe you need a laptop a dedicated graphics chip. At 1366x768 resolution, I am guessing you need something like a Geforce 820m or a Radeon R5 m255. But you are not going to find a new laptop with a dedicated graphics chip in your price range.
Perhaps it is best to post your question in a Minecraft forum since people there actually play the game and have a better idea of laptop in your budget range may be better than the one you selected with the A8-7100 APU. I can only make an educated guess. Also I just checked the link, the Acer laptop is now $460 so I guess it was a Cyber Monday deal that you saw. You may need to wait for a couple of weeks for Christmas sales to kick off to find something decent in your price range.