Projected Date Formula From A Combination Of A 2 Cells

I am trying to make the "Next Phase up DATE" cell automatically configure accorfing to the Issue date and the PHASE 1, PHASE 2, PHASE 3 Selection.

Phase 1 last for 14 days
Phase 2 last for 21 days
Phase 3 has no phase up date

So if I put 1 July 09 in Issued Date cell and select Phase 1, the "Next phase up date will be 15 July 2009. If 1 July 09 in Issued Date cell and select Phase 2, the "Next Phase up date will be 22 jul 09. If 1 July 09 in Issued Date cell and select Phase 3, the "Next Phase up date cell will be (N/A or something to that nature.) The Doortag portions are refrenced to the upper portions, so I only need the formula for (merged)CDE10 & (merged)CDE32