You can download it from the USCIS website from anywhere in the world. Go to www.uscis.gov, click on "immigration forms" and look in the list for the I-134. Or try the link below.
BE AWARE that this form requires some financial documentation that will be much easier for your spouse to collect while in the US! Make sure your spouse has a copy of the I-134 AND instructions and plenty of time before leaving the US so that your spouse can collect these documents before leaving to join you. If you need a co-sponsor (see instructions), that will no doubt be easier to arrange here in the US as well.
Best wishes,
Maya
http://www.uscis.gov/portal/site/uscis/men...00045f3d6a1RCRD