It doesn't look too bad. Koscielny has a little tightness in his thigh, and Ramsey an ankle problem, but not bad.
That's very good news, especially considering Ramsey assisted two of the three goals scored before he left the game. But, on the positive side, even if they were forced to miss some time, reinforcements are on the way with guys like Jack Wilshere, Mikel Arteta, Mathieu Debuchy, and even Abou Diaby (!) nearing fitness. If one or more is ready, it could be possible to simply rest Ramsey and/or Koscielny and let someone else take up the slack, especially as Arsenal's next opponent is Burnley.
If you're interested to listen to everything the boss had to say after the game, here's his full interview.