you can create a dual supply from a single voltage supply by using an amplifier as an "active" voltage divider. it's commonly done in onboard guitar electronics using an op amp to divide 9V into +/-4.5V... you will need something a bit more robust than an op amp for the supply you have. as you can see in the pictures, the op amp divider is very simple. for the resistors on the input side, use 1% tolerance resistors. in the second picture, it's exactly the same idea, the power amp circuit is identical except in size to an op amp. again, use 1% tolerance resistors for the input divider. it's a bit more involved of a project, but it can handle the complete 60V output of your power supply, and probably will work ok down to about 15 to 20V. you will know when it stops working, because the ground (actually the half way point of the input voltage) on the output side begins to drift
there are a few circuit notes you will need to know if you want to build the second circuit, such as where to mount the 3-diode string on the heat sink (they act as thermal compensation for the output transistors), etc...