Hmm, the going may get a bit rough here, but it'll make sense eventually. I hope.
I don't really know what you mean about changing yourself. There is nothing wrong with being an introverted and quiet person. Not at all. Being introverted does NOT mean you have to be a hermit. I think this is a common misconception. It just means you may have to change your style of meeting people...
Point being, a lot of non-shy, extroverted types will just say go talk to as many people as possible. This is good advice, and it will work. Questions is, how do you go about finding these people?
If you are shy (and I kind of hate that word), I would avoid big parties, night clubs, etc. They can be a bit overwhelming. Think about some of your interest, and find people that share the same interest. Focus on smaller groups. I think three or four other people is optimal. That way you won't feel any pressure to keep the conversation going, but you can add to it as you wish.
If you want to improve your social skills, I highly recommend
How to Win Friends and Influence People by Dale Carnegie. Ignore the hokey title. This book is full of great advice. Yeah, some of the examples are dated (the book was written in the 30's!!), but the advice is solid.
To summarize...there is nothing wrong with being introverted. You don't have to become the life of the party to have a fulfilling social life.
Your assignment: Write down your interest, and find a local group dedicated to your interest. If you can't find a local group in what you are interested in (I have no idea where you live), find a new interest
Or do some volunteer work.
Get to work!