VBA programming formula needed.?

Hi there. I'm writing a program in VBA, and need a couple of functions to convert a week number into Periods and Weeks.

The data is as such:

1 to be converted into Period 1 Week 1

2 to be converted into Period 1 Week 2

3 to be converted into Period 1 Week 3

4 to be converted into Period 1 Week 4

5 to be converted into Period 2 Week 1

6 to be converted into Period 2 Week 2

7 to be converted into Period 2 Week 3

8 to be converted into Period 2 Week 4

9 to be converted into Period 3 Week 1

10 to be converted into Period 1 Week 2

....etc

So I need a PeriodConvert(Value) and a WeekConvert(Value) function,

I've done it before with some REALLY ugly formulas, just wondering if there is a nicer way of doing it.

Many thanks