From Taruby's site:
This is Nekobyou Neko's second serious work after her yonkoma manga series "Ittan Neko." Although meant to be a single oneshot story, it later spawned additional stories using the same cast of characters before fading into obscurity. The first three chapters go by the title "Mahou Zakkaten Vi Via" while the last two go by the title "Bishoujo Mahou Senshi Catling".

By PsychoticEmo:

Ever since Joujiro was a little boy, he dreamed of becoming an ally of justice. One day, he meets Felvieno, a otherworldly being who owns a dimension-drifting shop of wish-granting items. Once Joujiro enters Felvieno's shop (which had taken the place of Joujiro's bathroom), Felvino offers him "whichever item he desires". Upon hearing that Joujiro wanted to become an ally of justice (after he practically threatened to kill him if he didn't take something.), Felvieno granted him a transformation bracelet. However, much to Joujiro's horror, the transformation bracelet turns him into a magical CATGIRL... Complete with boobs.

And to make things worse, it Felvieno is now stuck in Joujiro's dimension.

NOTE: Since this story is relatively unpopular, only magazine scans are available, hence the poor quality.