Which graphics card to get with my lenovo g505s?

Neither is very strong. If you already have the laptop the motherboard may or may not have an appropriate socket to add a card. If choosing between the two, they are both AMD cards. R5 M230 may be a replacement follow-on as slightly stronger as a newer version.
http://www.notebookcheck.net/...849.0.html
Rank 236 vs 240 on the large slow loading table.
Bioshock Infinite low settings on x768, the R5 got 35fps vs 28fps for the 8570m.
It shows a little stronger in Tomb Raider and Crysis-3 also.
In identical laptops, the R5 m230 is better.
http://www.notebookcheck.net/...655.0.html
vs
http://www.notebookcheck.net/...985.0.html