if i'm not mistaken, USA voltage is spec'd to +/-5% of 120V (someone correct me if i'm wrong). so, your voltage readings are a bit on the high side. take some measurements over the course of 1 week & see if you have consistently high readings. Of course, do double check that you are reading the #s correctly & that your equipment is correctly functioning.
power conditioning......hmmmmmm.....where to begin!!!
to get the voltage to 120V always you'll need a voltage regulator/re-generator like the one PS Audio makes (or some other brand). Most other power conditioners (like BPS, ExactPower, Richard Gray, Chang Lightspeed, Blue Circle, etc, etc) do not regulate the voltage; rather, claim to "clean" it up.
Do a search of these archives to find info & there is a ton of it here!
Each method - power conditioning & power re-generation - has its pros & cons. You'll have to educate yourself & decide.