Surfing Waves

I'm a beginner and I've been longboarding on my 9'6" for a while. I can catch and ride waves pretty well at this point but I'm still learning. Now I want to switch to shortboarding and I'm wondering what size board I should get. I'm 6'1" and 160 lbs.

I was looking at this board

cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290236915799&ru=http%3A%2F%2Fsearch.ebay.com%3A80%2Fsearch%2Fsearch.dll%3Ffrom%3DR40%26_trksid%3Dm37%26satitle%3D290236915799%26category0%3D%26fvi%3D1

It's a 6'10" egg shaped realm board. Do I need something bigger or should I get something smaller? Keep in mind I don't have alot of money and the most I can spend is around $150.

going for a six ten egg or magic carpet sounds like a good idea, i wouldn't go smaller than 6'6