Your biggest problem right now is that you don't know if AdWords is working for you. As others have said, you *need* to be tracking conversions, otherwise the whole exercise is pointless (i.e. you need to know whether advertising is resulting in sales).
Using AdWords is a just as much of a marketing strategy as any other. You need to devote time and energy to it. Once you know whether it's working for you, you can take the decision on whether it would be a worthwhile time investment to learn a bit more and concentrate your marketing there.
If AdWords isn't working for you, but other marketing channels are successful, I'd recommend sticking with and expanding your existing marketing strategies, and leaving AdWords well alone.