With what you are describing your only safe and legal option (short of replacing the incoming feed) is to convert the 240 circuit to a single, 15 or 20 amp 120 volt circuit for your receptacles.

Also, if the garage is detached there are other considerations involved when installing a sub panel.

This post was edited by joefixit2 on Wed, Sep 10, 14 at 9:49

Does the incoming line consist of two hot legs plus a neutral and a ground or just two hot legs and a ground?

A 240 circuit has no neutral. A 240/120 circuit has a neutral. So I am assuming the OP has no neutral, unless he is describing it wrong which is possible.