What Positrak suggests above is a useful item. It will allow you protection if a storm surprises you and can be driven while on... I've run mine at 60-65 mph. If you aren't planning to go doorless, it will keep everything dry. If you do remove doors, it will enclose the back seats, but leave the front exposed. It includes a couple of ponchos to wear or put over the seats in a pinch.
It is hardly a good option for extended use, but will allow you to "limp along" until you decide on a proper soft top. I have a hardtop only and run topless for about 5-6 months of the year. In the middle of summer, I'll usually have a bikini top on, but keep this emergency top under my back seat just in case.
I'll get around to buying a soft top eventually, but I'm not really in a hurry, especially with the gear I already have.