GTX1050ti and bit higher you will find here: https://hashcat.net/forum/thread-6098.html ,use google bit more. Also some of other cards for wpa/wpa2: http://crackingservice.com/v2/?q=benchmarks
For small budget you can go with 2 x 750ti, will be more power efficient and will be faster than your current 5870.
For small budget you can go with 2 x 750ti, will be more power efficient and will be faster than your current 5870.