I'm not hitokiri-san, but that's not a set phrase というと but just 'quotation particle と + verb 言う + conjunctive particle と'. The conjunctive particle と expresses that the subordinate clause is the trigger of the main clause, and is used to describe a past fact objectively here. (This と is close to たら, though たら sounds more colloquial.)
You could also translate that as "when I said '...', she took me to the store", but the idea is the same. In addition to と and たら, you might also look up ば and なら to see the full range of nuances. と and たら can have "if" or "when" as the English equivalent, while ば and なら are basically just "if".