Eventually the plastic gears on the electric or power radio antenna deteriorate, and the antenna no longer goes up or down. If you are able to find an OEM replacement it's a simple swap. Pad and Wheels has a good write up.
Third Party Replacements
The Metra AW12 (or PW12?) universal power antenna from AutoZone (about $40) fits. NOTE: The Metra PW22 won't allow the use of the trunk panel on that side as it needs to be turned 90 degrees.
"The Fuba antennas and their facsimiles all have an amplifier in their base in order to boost the signal and make up for the short mast length. They actually work really well because they used a good quality amplifier. Rather than picking up the signal with a passive antenna and then loosing some of it in the coax to the radio, the signal gets amplified from the get go. From what I can see of your setup, you screwed the Fuba mast into a standard passive antenna base."
The Honda S2000 antenna are also a good fit. You can get kits from ebay which *may* have the correct gromet to match the slope of the MKI.
Alternately, you can get the antenna assembly from any 2000+ GT/GTS Celica, the S2000 antenna just screws right on to the Celica assembly. You need Celica antenna parts 2,3,4,5. It appears that the fit is a little bit of a project to get the mount to sit properly, since the Celica the antenna assembly is at an angle where the antenna sits, and that area is more flat on the MKI. You can usually pick-up a used S2000 antenna on newcelica.org, for around $15.