You're probably there already with Lion (as your signature reveals).
The 2007 MBP is probably limited to Lion. An exact model would nail that down, but that's likely the answer
The iMac is probably actually a "late 2006" model, as there is no 2.16GHz 2007 iMac, and if I'm correct then that also is limited to Lion, so essentially you're done. Lion is no longer supported, so it will not receive security updates going forward.
As the owner of two 2.16GHz MacBooks, I appreciate the interest in keeping these going, but neither of them are fit to be anyone over the age of 6's main computer in the year 2015. You could add an SSD drive to them to perk them up a bit, but they are becoming increasingly obsolete and unsafe, and probably aren't worth the investment. I plan on adding SSDs to mine and giving them to writer friends who will be using them, essentially, as typewriters with email capability.
