I wouldn't recommend any more fish until AFTER the tank has cycled.
What you have now is not ideal I am afraid. Unfortunately, LFS are notorious for not telling you the full story.
We do prefer to promote 'fishless cycling' as you are not subjecting any fish to the stress of the cycling process. There are a few threads about this on the forum.
If you can return the fish to the LFS and adopt this route, it will be much easier for you. I would seriously recommend this and so would 99.9% of the Aquarists on here.
Please take a look at the links:
Fishless Cycling
Mature Media Donation See if someone in your area can donate mature filter media - it will speed up the cycling process.