Heat mat is a big no no... so is a heat rock!!! spraying hot water is useless too....
people brought up all the options to your solution... and 60-70 is a matter of weeks before your frog dies. It's like I'd toss you outside at 10Celcius without a jacket for weeks.. you'll survive a while but you'll break down at some point.
-Portable baseboard room heater (best way, expensive on electricity bill)
-ceramic heat emitter (pricy but best quality of heat for just one tank)
-red tint incandescent bulb (can stay on at night, cheap and efficient but will dry up a 10gal real fast)
Heat mat cannot burn a frog tho, I don't understand why people keep saying that eheh. the one for frogs are 4W... this is completely useless waste of money as this doesn't pull ANY heat at all... it's very minimal... but the thing you have to understand is frog burrows when they're hot and want to cooldown... so you mess that up for em big time with a heatmat.
heatmat are "good" for animals that don't burrow like geckos, toads, dart frogs. ultimately using it right under a false bottom vivarium will give you best results but in all seriousness, they're a complete waste of money for what they are.
Just get a good lamp and ceramic heat emitter
