Trouble in getting USPS Shipping response from API

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Ajax

MVC

hi,
i need to get show USPS Priority Mail Express 2-Day™ and USPS Priority Mail 2-Day™ response from USPS Server (United States Postal Service), on my Cart page to display the
Estimated Shipping charges for the users from their given shipping addresses.
for that i have USPS userid with url

http://production.shippingapis.com/ShippingAPI.dll?API=RateV4&XML=<RateV4Request USERID="XXXXXXXX" >
     <Revision/>
     <Package ID="1ST">
          <Service>PRIORITY</Service>
          <ZipOrigination>38111</ZipOrigination>
          <ZipDestination>80135</ZipDestination>
          <Pounds>1</Pounds>
          <Ounces>8.5</Ounces>
          <Container>RECTANGULAR</Container>
          <Size>LARGE</Size>
          <Width>15</Width>
          <Length>30</Length>
          <Height>15</Height>
          <Girth>55</Girth>
     </Package>
</RateV4Request>

I got response when i give directly give this URL on browser. Now i need to get response through code. i just checked about the code in NopCommerce , in that there lot of calculations iam totally confused.
Can anyone help me to find the solution?
Thank you