All oxalis types enjoy warm weather and mild humidity. They also like bright, indirect light, but usually can tolerate direct sunlight. Therefore, they do make excellent candidates for groundcover and outdoor containers. So yes, you can plant it outside.

However, your oxalis will be fine in its original container (at least, until it outgrows it, and it will...fast). Make sure it gets a decent amount of natural light and keep the soil relatively moist.

And it would agree with you, they are gorgeous...some of the most vibrant colors of any plant!