I bought one of these plants cheap in Lidl last spring and lost it last winter. It didn't make a whole lot of growth and flowered sporadically in the summer. I didn't have anywhere warm enough to bring it into - the polytunnel I begged a small space in was obviously not warm enough for it. Unless you have a heated greenhouse or conservatory it probably won't survive next winter.

If you're worried about bringing slugs and so on into the house, I guess people do that all the time - the spare bedroom is the traditional place to overwinter pelargoniums and tender fuchsias.

As stated, it is very tender.
I too have bought one from Lidl (a few weeks ago) very much eyes wide open. It's a small plant but was £1.99 against the £15.99 in garden centres.
My thinking is that as I can bloom a Hibiscus rosa-sinensis well in an eight inch pot with a regular feed regime, plenty of water and light then this could work well with the Dipladenia.
So mine will get an eight inch tomato pot, plenty of water and light (but not direct sunlight) and regular feeding when in growth. Mist regularly and keep good humidity around it (I've read that it's a spider mite magnet). Minimum temp is 13 to 15 celsius, if night temps are dipping below this it will perform poorly.
Come the winter, nip out the growing tips and place indoors at pretty near the minimum temperature with good light and water occasionally. I have no problem with direct winter sun, it's pretty lame and short lived. The important thing is to keep the humidity up at all times - stand on a tray of pebbles with water in (the pot shouldn't stand in the water though).
Prune it fairly hard in the spring to encourage new growth which is where it will bloom from.