The first point to make is that it is not up to her when you see the children.
As parents you and your wife are expected to agree how your children will share their time between you using Family mediation if necessary
If no agreement can be made then the court will make the decision.
The law says that the chidlren have the right to spend time with both parents and the courts will enforce this if necessary.
Unless there is some reason why you cannot keep the chidlren safe whilst they are with you then supervised ocntact will NOT be ordered (but to start with grab anything she offers)
If your working hours allow alternate weekends Friday to Monday and one night in the week plus half the school holidays is not unreasonable
With regard to the finances you will have to pay roughly 16% of your gross income as child maintenance - possibly a little less if you have the chidlren more than 52 nights a year.
There may also be some limited time spouse maintenance to be paid - but you certainly will not have to continue paying all the bills
I hope that this is of assistance - please ask if you need further details