If you cannot alter the laser focus then I have a lot of laser modules and I would be happy to sell one or two to you (PM me if you want). They are good to about 600m and have focusing on them (with flying leads, apparently 2.3-3v but I have run them off 9v and no issues for a short time - probably should have a resistor off 5v or 3.3v to get them to 3v or lower)