Canon digital camera question about increasing resolution of photos

Newbie. I have a Canon PowerShot SD850 IS Digital ELPH camera. I've taken a photograph with it and then transferred the photo to IPhoto in my mac computer. I asked IPhoto to tell me the resolution data for this photo and it said 640 x 480 pixels. Is there any way to increase the resolution so that the photo will be of publishable quality? Is there any way to adjust any settings in the camera so that I can take another shot and produce a photo with more pixels? Or is that the limit that this camera model can produce?

 

In the camera's menu, you should have a setting to change the resolution.
Mine (a Canon) is set to Large (L) which gives me a huge picture. (approx. 3072 X 2304 pixels).

I don't think you will be able to increase the size of the photo you have now and still keep any quality.