Since your tanks too small -- why not talk to the LFS and see if it will take back the tang for store credit.
Since you now have an ich infested tank you should setup a QT tank ... treat all fish with either hyposalinity or copper - the ich in your show tank will die off if you leave it without fish for 5 weeks.
Heres a link discussing ich and how to cure.
http://www.petsforum.com/personal/tr...marineich.html
Its real easy to maintain an ich free tank ... just QT your fish before you place them in your show tank.