Guardian angel vs life steal question

Had I game previously where I was having a hard time staying alive as kindred. GA and Bork came to mind but I wasn't sure what was more important in the situation I was in.

http://lolprofile.net/match/na/2563281720#Winters Kindred

This was the game im refering to. When should I prooritize ga vs life steal? Or should I not even worry about ga until I already have life steal?