Actually an increase in demand will simply lead to a higher price. No need to worry about the supply curve as long as it doesn't shift (of course there is a marginal shift of 25 BTC per block but I wouldn't worry to greatly about that in the short term).
the more users of BTC there are the less the supply will be due to smauging and lost private keys. the supply i think i was referring to was the supply in actual circulation because the real supply is fixed and will be forever.