Just cardio?

So I've recently dusted off the cross trainer and started using it again for its proper purpose not a clothes horse as it had become.

I'm doing around half an hour a day burning approx 300 calories.

My main goal at the moment is to lose weight but should I think about doing some other excercise as well?

Some days I walk at lunchtime so do less time on the cross trainer when I get in.

I also do about 20 pushups a day most days.