Need advice!

Because i dont drive my golf that often around my driveway, the battery is always a problem. Its a bad battery to start with, but its always hard to crank it. I usually do like 20-30min drives, just forward, park near the garage doors, reverse, then go left around the corner of my house. When i park it in the garage and come back to it after like 3 or so days, the battery is flat most of the times. My question is - is it the clock on the dash that drains all the juice from the battery, or is it just because i dont drive it that often? If its the clock then what can i do to keep the battery from dieing every time, because bump-starting every time isnt that fun. Thanks!!!

ps. I added some photos of what happened when i was driving. The little thing on the right side of the radiator that connects the radiator to the expansion tank broke off, because it was already broken by the crash. We superglued it, but it will need to be fixed more perminantely.

pps. Have a nice day!!!!!