Your users expect to get the most important information from you in the most prominent sections of your website. Here is how you should integrate your Toolbar into your current site promotions:
Promote it in a prominent place, above the fold.
Make sure that your homepage, as well as other high-traffic popular pages on your Website all highlight the Toolbar and link to the download page.
Use high-contrast colors so the promotion is prominent and noticeable.
If you have a section on your web pages where you run promotions (for example a rotating banners or a promotion box) be sure to also showcase your Toolbar - you should place a banner or a textual link leading to its Download Page.
Make sure your promotions are dynamic - users tend to ignore banners and ads that always appear in the same locations.