I'm usually in the camp of, "don't put it on the windshield if you know it's illegal," but since you're trying to fix the problem, here's my constructive advice.
Go to court and fight it. You should pay whatever the "fix-it" fee is, but shouldn't have to pay the fine for failing to meet it after the fact.
If it's mounted in the front bumper, which is physically in front of the vehicle, you're compliant.
"Sec. 502.404. OPERATION OF VEHICLE WITHOUT LICENSE PLATE OR REGISTRATION INSIGNIA. (a) A person commits an offense if the person operates on a public highway during a registration period a passenger car or commercial motor vehicle that does not display two license plates, at the front and rear of the vehicle, that have been:
(1) assigned by the department for the period; or
(2) validated by a registration insignia issued by the department that establishes that the vehicle is registered for the period."