First of all, if you are using Premiere Pro at all you want to go for a graphics card that will facilitate GPU acceleration. Neither of your cards listed would do that.
http://www.adobe.com/products/premiere/tech-specs.html
For After Effects, you want as much RAM as possible given your budget. I would view 4GB as not adequate, 16GB might be a minimum.
I just purchased a new editing laptop from Sager and so it far, I am quite pleased.
http://www.sagernotebook.com/index.php?page=product_info&model_name=NP8171
Also, if you want to check out ADK. They make computers designed for editing.
http://www.adkvideoediting.com/
http://www.johnathanyoung.com
