And if so, what should I do? Aiming to lose weight and tone up.
You can get fitter, but you won't lose weight unless you track your diet and work out where you're consuming calories in excess of your daily calorie expenditure. If you have a look at some of the cardio machines (eg the Ski-Erg or the Air Bike) you'll see that a tremendous effort will expend, say 100 calories - a third of a Mars Bar or the like.
So twice a week is better than nothing. How long have you got? You could do what's called "metcon" - metabolic conditioning - basically a fancy name for cross training and a mix of strength & endurance plus HIIT sessions.
I generally start with strength, after a quick run (5 mins) and mobilising as a warm up. I'm getting back to lifting heavy after a back spasm (caused by sitting too much!) - did 5 for 85kg deadlifts this week, after a warm up set of 10 at 45, and 8 at 70kg. With warm up, rest gaps between heavy sets and mobilising, that's generally around half the hour session. Then I do a mix of stuff, including stationary bike, running, Ski Erg (I love the Ski Erg as much as I hate the Air Bike).
If I deadlift one day, I squat the other day.
If you're not sure about lifting technique to go heavy, then things which take no technique (apart from head down, grit teeth, push) such as sled pushes are great.
For fun, add in things like box jumps, or box step ups with dumb bells, or work on your press ups, and so on.
The main thing is you should train to almost failure (not injury) - the last 2 one 3 reps in each set should be really tough, so you need the rest break. In HIIT, you can work at your current level, but add in something that makes it a challenge. For example, on a stationary bike, set the resistance at a difficult but not impossible level, and do say, 30 secs as fast as you can. Then 30 secs slow, then 30 secs fast. And so on.
Or do this running outside - sprint 40 secs, walk 20, sprint 40 etc etc (or adjust those timings, but it's easiest to keep it to each minute, IYSWIM) and repeat, say 10 times. It's a really quick way to build fitness. It's difficult, but it's only 10 minutes!