Although the cause of ice ages are not fully understood, but it has been said to possibly do with carbon-dioxide and methane concentrations, ocean currents but ofcourse also natural accurences like tectonic shifts, volcanoes, and so on and so forth. But obviously also the removal of ice caps, the ebb and flow changes, sea levels, etc.
It seems that the trend however is that as the earth warms up, eventually it reaches a point where there will be a turn around and dive back into an ice age. Predicting exactly how and when this happens is still way ahead of us, but it is prude to say that our climate influence negatively pushes this moment back. If anything, the climate changes we attribute to, is likely to speed up the process. Maybe only by a small fraction, maybe by a large percentage, can't really say without knowing what exactly causes an ice age. But it's still less likely that it pushes it back.
Note that we are currently in a natural warming trend regardless of global warming. If we were in a cooling trend the effect might be reversed and push the end of the coming ice age further away.
Whilest we have pretty good data on atmospheric concentrations throughout the ages however, there are many factors that aren't as easy to pin down such as what the ocean currents were like throughout the ages and what changed them over time. Not to mention that a difference of a few degrees celsius in an ocean current can have major global impact. That's not easily measured based on a few archeological and geological finds. :P
Basicly, if we are to attempt and draw any hypothesis from what we do know, I'm just saying it sounds to me like our tribute to global warming is more likely to speed up the coming of the next ice age rather than push it back.