Re-entering Canada

[L]

Does anyone know if I need to apply for a re-entry permit to get back into Canada if I go over to the USA for a weekend?

I've been here in Canada for 3 months now on Working Holiday Visa (Australian passport).  We are looking to go over to Seattle for a long weekend but my WHV says specifically that it dosen't entitle me to re-entry into Canada. Do I need to apply for a re-entry permit and where can I do this? 

As the trip is coming up very shortly, we are kinda of pushed for time, is there a way to speed things up?  We have not applied for temporary or permanent resident cards.

Also does anyone knows what the current visa status is of Australians and British citizens entering into the USA is?

Thanks in advance for any help offered, it's greatly appreciated!

[ghiaskhan]

If you return with in the validity of Visa,you willnot require re-entry permit.

[ghiaskhan]

Do ask the immigration authorities, before you move out.There may be a change in rules.