I don't think you can. DPSS lasers can be modified because they rely on a pump diode which is underpowered (in 5mW greens). Increasing the current to the IR diode gives it more power, but if you do this with a red diode, too much current will kill it. 4-5mW of 635nm will still be much brighter than any laser most people will have. I think I saw a 10mW 635nm laser somewhere...
I've heard that these have a pot on them on another forum, and that they could be turned up a little bit. I'm not trying to pop tires or anything, I just want a consistant 5mw normal operating power (rather than the 2-3.5 I've heard you actually get), which should be OK on these since what I've read says they're 7mw diodes.
I'm not sure, but I think the pot turns up the current, not voltage. I guess you could try the pot, but it might be a little risky. I had a 5mW red (650nm) and turning up the pot didn't do anything. Maybe you could try making a different driver? 3mW out of a 7mW diode does seem a little disappointing...