Ported box questions

I built a 1.57 ft^3 box for my 12" Alpine SWE-1242. At that volume, it can be either sealed or ported. I've been listening to it sealed for a while. It sounds nice, but I'd really like to try to get a little more bump out of it. So I'm asking for help on the port dimensions. I tried using WinISD, but don't think I know how to use it well enough to trust my own calculations made with it. Sub specifications: If you need any more info on the box or sub, please comment or PM me. Pics of the box can be seen here

Oh, and I don't think it'd make much of a difference, but that 1.57 ft^3 is without the sub loaded into it.