Having spell cards is a great idea - organizing them by monster is even better. Having a stats card with a little stylized picture on top of a bunch of spell or ability cards is possibly too far but I would definitely recommend it.
It doesn't take long to read spells once you get the gist of their layout, which is actually the largest barrier to understanding them. I'd sit down for a little bit and read the Magic section, understanding what 'Range' and 'V, S' and '[Fire]' mean, and when you do, reading the entries will be much quicker and easier for you.
Otherwise, rely on your players to allow you to retcon things if you screwed up, for example if the Caster put a spell down that didn't help them, or hadn't pre-cast Mage Armour, just say that they did, or didn't, as the case may be (although don't roll back rounds).
Finally, once you have some idea of how basic game effects like areas and effects (stun, daze, prone, damage, reflex saves etc) work, feel free to mix it up a bit. Sure, the book says that Fidelius the Enchanter has colour spray prepared, but perhaps he's a bit of a rebel and has invented his own colour blast, similar, but affects a line instead of a cone. Remember, Custom Spells and Spell Like Abilities are very much a thing, and you are the GM - if you say he invented a custom version, he invented a custom version.
For extra cool points, perhaps he scribed it onto a scroll, and the wizard could find it and use it! (and if you accidentally make something overpowered, you can then have fun with all the various drawbacks that manifest over time and are the reason that the magical community at large doesn't use this spell - involuntary transformation when hiccuping is a fantastic one, as is it slowly draining your wisdom so you do dumber and dumber things and become confused from time to time in stressful situations)