Calling (HttpWebRequest) WebRequest.Create

I'm trying to do something similar to the client-side XMLHttpRequest object where I call a web page in my site and pull back the rendered HTML.

I've been working with the HttpWebRequest which I believe is the the equlivant to the XMLHttpReqest, but the issue I'm running into is that I need to provide the fully qualifed http path.  Is there a way or method that I'm not using correctly in ASP.NET that I can make a GET call and retrieve the content like the XMLHttpRequest? 
1 try
2 {
3 HttpWebRequest request;
4 HttpWebResponse response;
5 Stream s;
6
7 // create a request to the url
8 request = (HttpWebRequest) WebRequest.Create("Collect.aspx");
9
...