Ordering hot food after cold at a Konbini

I go to the konbini for lunch a lot. I often pick up a drink and a few cold things before ordering behind the counter things. The problem is there’s no “non-awkward” way to do this currently. When they’ve scanned through all my stuff and then as usual always say the price, then say what I want. But I feel this is a little rude. I feel there must be some way I can warn them I also want hot food too. Really what I want is an appropriate phrase for:

“Oh, I also want...” or even just an “Also...”

Order you hot food before you give them your cold foodstuff to scan. Simple.

You could say:
- Kore (as you set down your cold items on the counter) to, XXXX mo onegai shimasu.
(I would like to buy this (the stuff you place on the counter) and XXXX too, please.)

Just before then scan the last item I say, あと肉まん, or whatever it is I want. I do this out of habit, I doubt I would be causing any huge inconvenience by waiting for them to finish scanning first.