You should just be able to co-transfect the cells with Lipofectamine. Especially HeLa cells since they are easily transfected. Are you expressing multiple sgRNA from a single vector or multiple? If you have them in multiple vectors you might have more success cloning them into a single vector. This was described in Nature Protocols 8, 2180–2196 (2013). If you have hard to transfect cells you could get a lentiviral expressing CRISPR vector.
@Kyle: Thanks for your reply. Yes I have different gRNA strings in PCR cassette with U6 promoter, which I have to co-transfect with the dCAS9 fusion protein encoding plasmid.