Are we evolving to age slower, or to live longer aging at the same rate?
The question has a more or less official scientific name - the grandmother effect (or hypothesis).   In the rational world of evolutionary biology, children love their parents for the same sort of reason - the parents give them resources to gather their strength and develop as adults so they can have their own children with the most advantage that they possibly can.  

Humans are off the charts in the amount of resources we invest in our children - our lives are 1/4 to 1/3 over before we sometimes leave our parents household (in some societies of course they never leave the house, but step into an extended family).  This may be one of the reasons we are so successful as a species - we live in practically every place we possibly could and have no danger of competition from any other living thing excepting ourselves.  

The grandmother effect is essentially the idea that if women, who are more attached to the offspring in more cases than fathers, continue to live and help support the grandchildren and make them more successful, then this will allow post menopausal women to have a longer lifespan (which they do). 

The evolutionary biologist Sara Hrdy, emeritus UC Davis, has written quite a bit about the nuances of the evolution of the role of motherhood - reading some of her articles or books might give you a deeper sense of how profoundly filial love has shaped human beings. 

--- more answer this stuff may or may not be worth reading depending on how broadly you want to understand this question...

Its important to say that many of the expansions of human average human lifespan have not been genetic.  Its commonly cited that sewer systems, clean water, antibiotics and plentiful food are the three most important factors in human lifespan - and before modern developed world nations, the average lifespan of human beings was somewhere in the 30s.  And there are significant lifespan differences in regions where these factors and others (education of women, access to prenatal and early care etc) are available.  

Studies continue to be published that examine environmental and lifestyle factors compared to genetics and it seems that environment and lifestyle can make an astounding difference.  

But genetics undoubtedly has a role to play here too.  There are probably some individual humans and animals which have evolved to live longer.  This has been found to be genetically related in some humans by demographics and family lines.  

Still there are genetic factors that are being identified.  I think its a common misconception that evolution changes the entire species, but its not really true.  There are some who have that tendency and others who do not - at times there will be more of say shorter lived people and other times longer lived individuals will be more common.  It depends upon whether the living conditions of the population really favor one tendency over another.  Usually shorter lived individuals can assume to have other advantages, say the ability to store energy more efficiently.