Quantify RNA transcripts

[Hinayana Bawagan]

I use RNA transcripts directly from the transcription reaction (w/o DNAse 
treatment) for electroporation.  I run TBE 0.5% agarose gel to check tthe
quality of my RNA transcripts  using HindIII lambda DNA markers.  I get a nice 
thick band but I have not yet quantified my RNA.  I know the concentration of mystarting DNA template and according to the company protocol I am following that starting with 1.5-2 ug of DNA I will end up with up to 12- 25 ug.  But I want tobe able to obtain the actual value not just based on prediction. 
 
Thank you very much/