I would go to consumer affairs and explain what happened. As the contract of sale is the supply of product for money and the product hasn't been supplied the contract is null. If you were given a verbal indication of the time frame then there is no issue with requesting a refund if this is not met. In saying that good customer service would be "Sorry mate, I can't get this in for a few more weeks, would you interested in this bike. I know it's a little more pricey but I can take $xxx off it"
This is from the Competition and Consumer Legislation
Section 36
(4) A person who, in trade or commerce, accepts payment or other consideration for goods or services must supply all the goods or services:
(a) within the period specified by or on behalf of the person at or before the time the payment or other consideration was accepted; or
(b) if no period is specified at or before that time--within a reasonable time.
Note: A pecuniary penalty may be imposed for a contravention of this subsection.
(5) Subsection (4) does not apply if:
(a) the person's failure to supply all the goods or services within the period, or within a reasonable time, was due to the act or omission of another person, or to some other cause beyond the person's control; and
(b) the person took reasonable precautions and exercised due diligence to avoid the failure.
(6) Subsection (4) does not apply if:
(a) the person offers to supply different goods or services as a replacement to the person (the customer ) to whom the original supply was to be made; and
(b) the customer agrees to receive the different goods or services.
From the way I read this, you could have a bit of a grey area, as subsection 5 states that subsection 4 is negated if the delay in receiving the bike is beyond the control of the LBS, which is entirely possible. Though the due diligence means that the LBS should have made sure that they could stick to that time frame. However subsection 6 demonstrates that the LBS should have offered different goods, IE another bike like what you were after and I think that's the key to this.
I looked for more on supply and sticking to a time frame, however I have run out of time on my lunch break. I can look further if you like later on.
If you paid by credit card, call your provider and report as fraud. Charge backs work well, take time, but work well.
Essentially though for future reference, never pay full for a product you can't walk out of the store with, pay a small deposit if needed but not full.