You can easily do this by creating Animation Clip for the gameobject. The way to do this is very simple,
- Select your gameobject
- In Unity3d Menu
- Click On Window
- Click on Animation
- Create A New Animation Clip
- Add Curves for Both position as well as Scale as well as Position Component of Transform.
- Create KeyFrames and just simply change the value of Scale And Position Component of Transform to your desired values
If you want the video tutorial to follow, then this is a very easy video tutorial from Will GoldStone. Here is the link http://www.youtube.com/watch?v=XGKyXdW74vU
If the steps above donot solve this , video tutorial will easily solve this. If you still have any doubts do write them in the comments.