My aim ... as a beginner ...

I am PC tech and I have never touched any programming before however I have little knowledge of web design with HTML/PHP, and I really mean the very basic level.

I would like to get in to programming, my aim is to create a piece of software for my parent's takeaway a EPOS (Eletronic Point of Sale), which allow us to ditch the paper and pen. The software I think it will increase our work efficiency and reduces the mathematical error i.e. working out a total cost for an order.

I am planning to modify my netbook Asus eee PC with a touchscreen to suit this software.
Looking to implement some kind of telephone number detection as well.

So question is:

Which language will be best for creating a POS software?
Anyone project build thread/open source POS software out there?

Please say it out if i'm a retard because I am think it abit over my head lol...