Your meter can only give an adverage bg of a snap shot of a moment of time... How near it might be to a HbA1c will be totally dependant on how many tests it's working on, when you tested and whether there has been any increase/decrease in sugar levels between one test to the other.. The less test, the less accurate it becomes..
It is worth though, written down the adverages on the day you have your bloods taken, then compare this to your HbA1c results, you will need to do this for several HbA1c tests to get a reasonable idea, but if the HbA1c is vastly different to your meter readings then it could indicate large or prolonged spikes between tests, worth investicating with more BG tests, if they are reasonable near, then you know that can use the meter adverage information as a indictaor of how well you doing..
Once you sussed out your meter you can in time, estimate a probable HbA1c for a forth coming test, but the real use of these adverages on the meter, is a quick referance guide, if the adverage goes up, you need to look at your individual BG data, to see if you can find the reason for it.. If the meter Adv is in target range, you know you plodding along nicely, if you are working towards tigher control, and the Adv is going down, you know you'll getting there..