You can do this before you finish putting the tyre on the rim (though if it goes wrong this can be messy) or inject it in after you have got the tyre on.
That little bottle is designed for refilling sealant if you have had a puncture. Buy a big bottle and a syringe.
Do I need an injector for that caffe latex stuff?
More shit to put into or around tyres. WTF
http://www.wiggle.co.uk/effetto-mariposa-caffelatex-zot-nano-repair-liquid-10ml/
and
http://www.chainreactioncycles.com/effetto-caffelatex-remover/rp-prod150133
EDIT: No. Just use a chemist syringe.