coby 7012 dropping and creeping

[themadness]

angry birds, dolphin browser and even a couple of utilities have been dropping for some unknown reason. i have gone from around 50/50 used and free space tp 67/33. i cant really figure it out. the screen has been somewhat unresponsive as well. i picked up a micro sd but havent really got a clue what its worth as i tried it and didnt change much.

can someone help please