I assume you're not taking Cipralex for insomnia, so if this isn't effective for anxiety/depression I'd try another SSRI, or maybe a TCA first.
I would not take mirtazapine as the primary treatment for an anxiety disorder, or anything less than very severe depression and then only until it lifted at which point I'd switch to something else because mirtazapine is notorious for pooping-out.
If insomnia continues to be a problem then low doses of immediate-release trazodone (Desyrel) would be my first choice.