Those running tights and long sleeve jerseys will be great. They key is layering. Running attire should be perfect for that, thin and lightweight make good layers. You don't need cycling specific stuff, but I do wear cycling jackets. If I could only buy one thing to get me through a winter of riding, that's what I'd get. I wear non-cycling gloves, base layers, and socks with great results.
I ride down to 25º, and I hate being cold more than anything. Once you get going, you warm up more than you think.
Also, try keeping a journal so you know that when it's x temp, and x wind, you wore x, and how you felt.
'02 Eddy Merckx Fuga, Selle An Atomica
'85 Eddy Merckx Professional, Selle An Atomica
'10 Soma Double Cross DC, Selle An Atomica
Slacker on wheels.