its been appreciating... ur text book will be out of date, the rapid appreciation has only been fairly recent
its been appreciating for a number of reasons.
interest rate differentials between here and the US mean we are attracting more funds going to investment than america, there fore demand for $A increases
america has been in a recession
America ended its policy of maintaining a high dollar (stupid bush govt thought it was best for the unemployment) but he only recently reaslised if he let the dollar work with market forces things would be better
umm... thats about it.. in relation to external stability, it has an impact because if our dollar is high, imports become cheaper and exports become more expensive for people to purchase therefore we become less competitive on global markets. we will tend to purchase more imports than we will sell exports which means that our CAD will increase as export income may not be able to finance import spending...
i hope that helps.