Kelly,
Are you using Lead Status to track SQLs? If so, you can pull that from the CRM or from the Leads by Status report. You could then add the first touch as a field, assuming you are already tracking that.
Some firms use a "First Touch" and "Last Touch" field that fills in the SFDC Campaign ID# or name and then you can report on that. You could also pull an SFDC Campaign Report.
If you are using RCA, the Program and Opp Analyzers will show the first touch and subsequent touches.