After your 6 week mark (and remember, some people need longer), you can step up the speed of your walking and introduce some smaller hills (with a gradual incline). Gradually build up to running.

You will need to wait a little longer to work on your core muscles. But when you're ready, you can start to do some things like The Plank (or hover). Tricep pull downs will help with your tummy muscles but shouldn't be done until around the 3 months mark.

Some cycling if you have a bike

Squats.

Have you looked around to see what's in your area? I understand about the financial side of things but some areas have free mums and bubs walking groups run by PT's. Many gyms will also do a Mum's and Bubs exercise session once a week for minimal amount - I think my gym was about $10 a class.

You can also do swimming. That is great for your core.

You may be able to start water aerobics again so long as you listen to your body and don't do what it objects to!

Good luck!

MG