I need to have the phrase translated into latin:

Opportunity at last!

We are moving our business and it has taken two years to complete.  We
are moving to Opportunity drive.  We want to use this as our slogan
for the move.

hi lrweston-ga -

Congratulations on your move.  Your new address is a great omen and
you know how the ancients regarded omens!  So Latin is definitely the
language for your endeavor.

Here are translations along with their literal meanings.  You can take
your choice based on the exact meaning of what you want to convey.

1.   Opportunitas tandem idonea  (Literally: the right opportunity at last)

2.   Opportunitas tandem (Literally: the opportunity at last)

3.   Opportunitis vicis tandem (Literally: at last an alternative chance)

In Latin, "opportunity," can mean, among other things," chance" or
"convenience."  To nail the meaning, it best takes a qualifier, which
in your case would be "idonea" meaning suitable or proper.

However, it would not be wrong to say "Opportunitas tandem" as you
mention in the Comments Section.  However "vicis" connotes "instead
of" or "alternative" as in "vice versa"  or "vicar" or
"vice-president."  So "Opportunitas vicis tandem" would be
restrictive.

I would suggest the first translation.

opportunitas
http://catholic.archives.nd.edu/cgi-bin/words.exe?opportunitas

tandem
http://catholic.archives.nd.edu/cgi-bin/words.exe?tandem

idonea
http://catholic.archives.nd.edu/cgi-bin/words.exe?idonea

vicis
http://catholic.archives.nd.edu/cgi-bin/words.exe?vicis

In the comments, you asked about different meanings.  As you're
probably finding out, Latin uses words in a subtle way.  Shades of
meaning are found in the placement, endings, or modifiers of Latin
words.

I hope I've given you the "slogan idoneus" for your momentous move. 
It will certainly promises to be a classic one.

alanna-ga

Thanks your input is greratly appreciated, we will go with Opportunitas tandem.

"Opportune" could be enough.
Its means "In a favorable place" or "At the appropriate time"
U could write "opportune!"
the other solution could be  "opportunitas in fine"

Thank you, your translation is now another version we need to
consider.  This is more difficult than I thought "opportunitas tandem"
was the last one, along with "vicis tandem".  Do these have differnt
meanings?

I think "Opportunity, at last!" is fine as it is.

"Next stop, Opportunity" or "Welcome to Opportunity" or "Our address
even says 'Opportunity'", or "Opportunity: it's what's for dinner"
would work.

Man, I gotta quit coming by here before lunch.

Hi,
Unless you are really set on a Latin slogan, and it makes sense to
your business or customers, I think Markvmd's suggestions put the
point across much better.

Being no Latin scholar, I probably shouldn't comment on yours or
Neuromancien's suggestions, but I think "in fine" suggests a finality
that is different from the English "at last!"  (gasp, we're there!). 
Your "tandem" may be more correct, but the first association with the
word is that of a tandem bike, which detracts from what you really
want to say, at least IMHO.  :-)

Good luck in your new environment!

Perhaps:

Occasio Denique!
Occasionis Deniquem!