Argh! Quick macaron filling help.

[MyDaydream]

I just read on another thread about buttercream melting in the heat. I've spent all bloody day making macarons for my mums birthday and planned to fill them with different buttercream flavours without even thinking it would melt in this heat.
So what can I do instead. I wanted lemon, raspberry &white chocolate, and cream caramel. I don't have a massive baking store cupboard but I have the stuff for buttercream obviously.
Please help, I've spent all day doing this. I'm already going to be up late finishing things off. I can't go to any shops and I can't do it tomorrow because she's coming over at lunchtime.

I have a macaron recipe book here

White chocolate ganache?
Lemon curd?
Can't say whether they will melt but they're not buttercream. I can post the recipes if you want

There is also a mango, rum and white chocolate which looks delicious but perhaps a bit too off the wall!

If you could post the ganache recipient that'd be great, I've got one here for lemon curd. It's worth a shot.

Ok here goes:

150g/5oz white chocolate finely chopped
5 tablespoons double cream
1 teaspoon vanilla extract

Put chocolate in small heatproof bowl
Put cream and vanilla extract in a small saucepan and hear until the cream has come to the boil
Pour the hot cream over the chocolate and leave to melt for 1 minute
Stir until smooth then leave to cool
Cover and refrigerate until thickened

In the book they put a whole raspberry in too, looks delicious! I've just realised I can do a photo so here you are