In case of the former, Sheet Music Plus has a large library of sheet music for Taylor Swift's songs. The music comes in the form of song books - physical, paperback books with a set of staves and musical notation for each instrument involved in each song - from piano through voice to flute. The books typically cost around $20 and are dispatched quickly. The page to buy the songbook for the album to which 'Love Story' belongs, 'Fearless', can be found here: www.sheetmusicplus.com/title/Taylor-Swift-Fearless/19118706 In some cases, instruments such as flute may be transcribed for piano in the songbooks, but the notes are usually the same and the sheet music will be readable for flautists.
For the latter, Ultimate Guitar holds the largest number of accurate guitar tabs available anywhere in the world. The highest rated page for 'Love Story' chords is located at tabs.ultimate-guitar.com/t/taylor_swift/love_story_ver3_tab. and shows the guitar chords in relation to their position around the vocals in the song, making them easy to interpret.