You probably already use a mail signature with your contact information. Use your mail signature to market your participation at the expo by inserting the web banner into your e-mail signature.
It will be appropriate to use your "Meet-us-at-DiaLabXpo" banner in your mail signatur
It is quick and easy to use Facebook to promote your participation at the expo. Facebook is a good channel to increase the level of awareness of your business and to create awareness about your participation at the expo. This ensures that both new and existing customers visit your stand.
Download a general webbanner and apply this on the social media.