TCP/HTTP POST for wunderground

I think it's been covered elsewhere, however in this instance am unsure if it will work with my issue.

On my Mega with an Ethernet Shield I have several sensors showing on a website run from my Arduino.
To upload the weather data to WUnderground I currently have to click on the URL to push the data out.

Is there a way to auto-send the data every say 5 minutes? I am aware that Blink will be needed for timing rather than delay.

The URL generation code:

            client.print("<p><a target=\"_blank\" href=\"https://weatherstation.wunderground.com/weatherstation/updateweatherstation.php?ID=****ID****&PASSWORD=********&action=updateraw&dateutc=now&tempf=");
            client.print(DHTo.temperature * 1.8 + 32);
            client.print("&humidity=");
            client.print(DHTo.humidity);
            client.print("&soiltempf=");
            client.print(sensors.getTempCByIndex(0) * 1.8 + 32);
            client.print("&soilmoisture=");
            client.print(soil);
            client.print("&baromin=");
            client.print(bme.readPressure() * 0.000295333727);
            client.print("\">Upload to WUnderground</a></p>");
            client.println("
");

First of all, which Ethernet chip are you using? Wiz5100 or enc28j60?
What you are trying to achieve is to have the arduino working as a "client" not as a "server".
You need a webservice (PHP for example) which get the data and store them in the database or do anything else.
I tried a lot to get a workaround but never could achieve this. Because between sending the first request and receiving the response the ethernet module stops working. But as a server YOU send a requst to arduino, this works well.
Maybe someone has similar experience with the ethernet module.