I am owner of an existing (3 yr. old) domain http://www.22shrutiharmonium.com and my website appears at the top of the search results in case of some search phrases like "22 shruti" , "22 shruti harmonium", "shruti harmonium" etc., in major search engines like google, bing, yahoo etc. My website has also been listed in Wikipedia (http://en.wikipedia.org/wiki/Harmonium).
Now, I wish to provide more generalized information on my site and hence I want to change the domain name to www dot 22shruti dot com.
Please guide me, about the ways / steps to retain the search engine credentials of my website OR, if not, then minimize the decrease in ranks, if I change the domain name.
Note : My website has windows web hosting.