The swap is pretty simple. I've done it a couple of times. Once on a '97 Cadillac Deville and once on a '95 Pontiac Bonneville. You can swap in a fixed mast antenna or a power one. but it wouldn't be that much more expensive to get a power one at a junk yard. Antennas for your car should be plentiful and cheap. The one I bought for my Bonneville only cost $12. Any antenna from a '92-99 Olds 88 or Pontiac Bonneville should be a direct bolt-up. A Cadillac Deville'* antenna will slide right in but you may need to use the anchor bracket from your antenna to make sure the bolt holes line up correctly.
My advice would be to get one from a newer car, say a '98 or '99 model. Avoid any that are fully or partially extended and especially ones that are bent. Chances are they don't work any better than the one you have and they'll be harder to pull back through the fender. An antenna that'* fully retracted most likely goes up and down properly. The junk yards I use give a 30-day warranty on all used parts, which is enough time to establish whether they work or not.
Removal and installation is very easy. You'll just need a socket wrench. To access the antenna, you'll need to take the jack out of its plastic storage case and then unbolt the case from the inside of the fender and pull back the trunk liner. Just disconnect the antenna cable, the power wires and the drain tube, then unbolt the bracket that anchors the antenna to the inside of the fender. You might want to clip the power wires and take the connector with you on the off chance the connector on your car is different. Chances are it won't be, but as soon as you leave it, you'll likely need it.
Once the antenna assembly is loose, just pull it out. The rubber grommet on the fender will offer some minor resistance, but just keep pulling and twisting until it releases. The grommet will stay in place but if you want it, you can pull it out after the antenna is removed. Installation is the same procedure in reverse but I'd suggest testing it before you completely button things back up.
The nice thing about harvesting our own parts at a u-pull-it yard is you can figure out how to remove and install things before you attempt it on your own car. And the staff generally don't care how brutal you are to the donor cars.