What should I buy for my trip?

[Gator Diver]

I am planning a dive trip to cold waters (62-68 degrees) for me.
I currently dive a 3mm one piece (Florida ocean and spring diving) and was wondering
what I should purchase for my trip that I could use
when I return back to Florida. I know a 7mm one piece would keep
me warm on my trip but I don't see much utility in it after
I return home. All suggestions are appreciated. Thanks.

 

[Gradual Ascent]

I think a two piece 5mm or 7mm would be the way to go. You can still use the shorty in Florida as a tweener.