You use a Mac, correct? Generally the best tool is LensFix, from Kekus (kekus.com) which uses the epaperpress profiles, and is also based on panotools from Prof. Helmut Dersch. Kekus put a reasonable front end on it and markets it for a relatively low price. This is the software to use with cameras and lenses that don't mess with the distortion in firmware/software themselves, ie with lenses on the m4/3 Panasonics that Panasonic doesn't make.
Don't use this with images that are produced with Panasonic lenses, as that will mess things up since programs like Silkypix (ugh!) and Lightroom know about the Panasonic tags for correction and do the job in software if shooting RAW, and if shooting jpeg, the process is done in camera.
Panasonic does this in camera so that lenses like the 7-14 can be made (relatively) inexpensively, small and deliver outstanding quality. They let the distortion fall where it may and concentrate on other aberrations, and then do the distortion correction in processing. An excellent tradeoff, but one that interferes with programs like LensFix.
I've used LensFix and panotools for years, and relied on them when using lenses with bad distortion. They let you tweak the profiles, and make your own for lenses not listed with a bit of effort and make architectural photography possible with all sorts of lenses.
If you want to do full perspective correction in software, ie using a centered wide angle to obtain the result of a shift lens, then you need Photoshop or something like it to do a somewhat reasonable job.
Henning