Magazine publishing software

Hi there,

My company produces advertising directories. Currently all the adverts and layouts are constructed in CorelDraw. Currently all ads are imported into single continuous pages before converting to PDF and then converted to printers' spreads in Acrobat.

We are looking for a way to streamline our workflow and I am looking for some software (online?) that can make the construction of the magazines way more efficient. 

I'm kind of thinking that there 'should' be something out there that will allow us to drag and drop our adverts into pre designated pages but am struggling to find something.

Is there anyone on here that does a similar task that can shed some light on a solution please.

Any help gratefully received.

John