shazzylynne, Look up train times on the German railways site: https://www.bahn.com/en
You can also buy tickets for trains within, to or from Germany on the same site, but not for trains totally outside Germany.
For long distance tickets buying in advance is cheaper, you get a print-at-home ticket e-mailed to you. BUT, once you buy, you are commited to the train listed on the ticket. No (or limited) refunds.
"where is the station in relation to the airport?" - there is a station at the airport (actually two), that is normally how you get from the airport into the city, a "main station" ("Frankfurt (Main) Hbf") in the city centre, and dozens of local stations called Frankfurt-xxx.
Most people recommend not to buy train tickets in advance after an intercontinental flight, because you cannot predict when you will exit the airport.
Are you flying to Frankfurt and travelling to Budapest the same day? If so, why not book a connecting flight to Budapest.
Edit: I have never heard of "Komarno", Wikipedia lists 5 places of that name:
* Komárno, a town in Slovakia
* Komarno, Lviv Oblast, a city in Ukraine
* Komarno, Lower Silesian Voivodeship, a village in south-west Poland
* Komarno, Lublin Voivodeship, a village in east Poland
* Komarno, a settlement in Crmnica, Montenegro