I offer a very nice kit called The LaserBoy Correction Amp for exactly this type of application.
http://laserboy.org/forum/index.php?topic=561.0
$40 plus shipping.
This kit is designed for audio DACs that output all positive voltage. It works very similar to the schematic that was posted above but instead of a fixed +5VDC regulator, it uses a variable negative voltage regulator that goes into the non-inverting input of the op-amp. The driving signal goes into the inverting input, so your control signal ends up inverted. No big deal. You just invert your control signal in software. The nice thing about this kit is that is it very easy to tune it for just about any kind of computer controlled DAC that operates in the all positive voltage domain. The kit comes with all the parts including the DB25 ILDA port and a DC/DC converter that operated on +5VDC and provides +9V and -9V for the TLO82 op-amps, so you can drive the board with USB supply voltage. All of the precision resisters were measured and matched to 3 digits on the meter. The board is populated for 6 channels so you can use it to drive scanners and 4 channels of color modulation. The color mod channels have 5V zener diodes on them to prevent anything over 5V from getting to your color mod inputs.
PM me if you are interested.
James.