>> The Amex representative advised me that I would not even be allowed to make a $1,000 purchase given that it is a new card.

Often times those reps make things up. Not sure why you even bothered to call to begin with. Just make the purchase. If declined, then you call.

>> You could also try to check your spending ability - there should be a link in the lower right hand after you log in.

For USA cards, yes. Cards issued in other countries (like OP's), no.