If you have to ask if you a system is good enough to sell, chances are that you have much to learn about the math behind testing and developing systems. Consequently, your system will most likely fail. This is not being said to discourage you, but rather to encourage you to learn more before proceeding.
Also, much of the past 15 months presented market conditions that were not faced for many years before. Sampling the system during other time periods is a must. Test statistics such as profit ratio and sharp ratio assume that your system's success is based on factors that are causing the market to move. More likely, your system made its profits in the back-test due to correlations between different conditions (IE: Different indicators working together to give a trade). Such systems are poorly evaluated in terms of profit ratio, sharpe ratio and such since correlation between factors can change dramatically over time.
It looks like you are trying to take a systematic approach to trading which shows that you are going in the right direction. My advice: Pick up some textbooks on statistical analysis and study them thoroughly while doing practice projects along the way reflecting the topic you are studying. Topics such as probability distributions, correlation testing, and hypothesis testing with mean and variation should be emphasized. Entering the trading game means you are competing with some of the most intelligent and knowledgeable people in the world. Do not for one second think that "winging it" is good enough.
A good book is "An Introduction to Statistical Methods and Data Analysis" by R. Lymann Ott which can be found at :
http://www.amazon.com/Introduction-...=sr_1_1?s=books&ie=UTF8&qid=1288640834&sr=1-1
Reading this book won't make you an expert at trading. It is however a good start to developing an objective approach and testing method.
If you do take this route, one piece of advice: Do not assume that samples of market data are normally distributed or even come from normal distributions. This makes a huge difference in the accuracy of your tests (If you are unsure what this means, you will understand it after looking into that book).
I am sure this post will result in replies saying "you don't need math" to be good at trading. Perhaps they are right. However, you don't have to be more than 6 feet tall to play basketball in the NBA, but it sure makes a huge difference.