As ever, variety is the key. Just moving about more will be an enormous help.
Walking, the bike and strider are all excellent cardio-vascular exercises - they get your heart and lungs working.
You know how much exercise you can manage. As it gets easier, increase the tension on the machines and the length of exercise. Set goals and targets.
Pilates will be good for stretching.
Don't forget you can get excellent exercise by putting on your favourite music and dancing around (best when the house is empty!).
So, you want regular exercise but a variety. It seems to me you don't need a personal trainer. You can make your own plan and set your own targets.
Muscle building would be good. You can get books out of your library that give simple exercises using things around the home. That will be an excellent start.
Swimming too! That will get you moving in a different way.
You are doing brilliantly and should be very proud of yourself.
Don't forget that as you get fitter you will develop more muscle. Muscle weighs a lot more than fat, but takes up less room. It is important for your morale that you measure inches and keep a record. That will show your true progress - the scales aren't always the best record.
And horror of horrors - if you have a digital camera get naked and take photos. Now, today, from all angles. Be brave!!
Do the same every three months or so - you will be able to see the difference, I promise. :)