So I have recently installed a HD7770 along with a new power supply - Antec VP450P.
I have noticed a increase in my CPU temperature from 31 to 35 degrees on idle while on gaming from 40 to 48-50 degrees.
Are these normal ranges for my CPU after installing a new GPU (using integrated before) ?
My CPU is a i5 3470.
Also could someone recommend me a good program for monitoring GPU temperature?
There is a good chance that the card is heating up your case, try getting another exaust fan, and also try it as an intake fan, and see what works.
Going from integrated to a powerfull gpu will increase case temperature because the card will radiate heat.