Keep the road bike, at least until you upgrade to a better road bike. The geometry is too different for Tri/TT bikes, and you'll likely find that you're less willing to ride the expensive bike in inclement weather. The first time you have the TT bike on slick roads, you'll understand.
I love riding my TT bike, even for casual rides, but even a complete Fred like me knows not to take it on crowded trails or on group rides.