extracting url in the code

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C#

.NET

Hi
I have following code that reads a webpage

 using (Stream stream = request.GetResponse().GetResponseStream())
{
  StreamReader sr = new StreamReader(stream);
  htmlpage= sr.ReadToEnd();
  sr.Close();
}

once i get the webpage I am trying to get my website urls extracted to make sure they are correctly being forwarded.
My problem is when i get url out, some come out fine while some have extra code infront and end of the url for example

(Javascrip:xyw('http://www.mysite.com/xyzpage.html')
I am trying to get rid of anything infront of and at the end of url so i end up with
http://www.mysite.com/xyzpage.html
I tried following, which doesnt work at all

string value = Regex.Match(str, @"\((\w+)\)").Groups[1].Value);

any idea how to write that regex as I am not good at it.