I weigh a bit more than you do (240 without the bike), and I run 700x35 Paselas on my Atlantis at 75 psi with no problems ever. I'm sure I could go at least 5 psi lower without pinch flatting on decent pavement, but there's not a lot of that around here...
I think your best move would be to go up a size or two. I rode for years on 25s and 28s before switching to 32s and 35s (Grant Petersen recommended it for riders my size when I bought the Atlantis), and the larger tires made a big difference. Paselas (which I love, and have put on all three of my road bikes) run very true to the labeled sizes--my 35s measure 34.5--and come up to 700x37. If you can't find them anywhere else, look here:
http://www.rivbike.com/products/list...product=10-071