Sally,don't apologise.We all had to start somewhere and oh how i wish there had been a site like this when i started out,instead of learning by trial and error.
The trouble with frogs and newts is that they don't always do what it says on the packet!! in other words though you expect them to be in the pond in spring and summer and out hibernating in winter it doesn't mean they will be.My frogs are to be found in the pond one minute,hopping around the garden the next.Generally though when it is hot and dry they will retreat to the pond but at night,and days when it is wet they are around the garden looking for food.In winter some of my frogs hibernate in the mud at the bottom and some under rocks and logs,and under my shed.
If you have a split liner then it is probably because it is old and worn,so you never know when it might get worse lower down.It would be awful to wake up one morning and find all the water drained out,which wouldn't affect the adult amphibians but would kill any young newts and tadoles,and of course all the insect life that is so important to the balance of a pond.
I would most definitely recommend you do it as soon as poss, then you will not only have the pleasure of seeing them enjoy a bigger better pond but you could be averting a disaster.
Just ask for any advice you need.Always happy to help,there are lots of us on here who are pond mad!!