As Phil682961 states above this could also be "I know and I am showing you." which uses the Present Continuous in English since in Greek the same form is use.
However, to introduce a future tense "...I'll show you" would not be a possible translation since the Greek is in the present tense.
Ξέρω και εγώ να σας δείξω means "I also know to show you" because Ξέρω=i know, και εγώ=me too, να σας δείξω=to show you. So it could be used p.e. if you wanted to reassure someone that not only your friend knows to show him (how to do something, where is something etc) but you also do. "I know and I am going to show you" would be "Ξέρω και θα/πρόκειται να σας δείξω"