Sound advice
Congrats on tying the knot Dewix,
From the info you did provide, to save yourself a world of hurt in the long haul, (I'm sure someone's speech at your wedding reminded you that her family are now your family)
as a bare minimum follow the sound advice from several other posters above:
1. Don't waste time fixing up every thing, go for a fresh install (time allocation: 2 pints +? for installing apps)
2. Harden her preferred browser with the suggestions by the venerable rm -rf *.*, ghostery and self-destructing cookies also recommended to minimise her browser slow down and reduce future attack vectors. If she likes watching the occasional cat video on youtube, add https://www.youtube.com/html5 to her bookmarks.
(time allocation: 1 pint)
3. Change her user account to remove useless start up apps and remove admin privileges.
4. Setup remote management so you can do future maintenance from home via VNC (3&4: time allocation 1 pint)
5. Use carbon copy cloner to make a fully functional back up, so no matter what happens you never have to sit around your inlaws drinking pints on sunday afternoon unless mandated by law. (time allocation: Sunday Roast)
As several people have mentioned, AV on it's own isn't worth a whole lot and probably won't save you from tech support emergencies during an FA cup final.