Highlight a selected row

Hi,

I have some code which highlights an entire row depending upon which row is selected:

Private Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)
Cells.Interior.ColorIndex = -4142
With Target.EntireRow.Interior
.ColorIndex = 6
End With
End Sub

This works nicely but has two problems.

1) It removes all current cell formatting - which i would like to keep

2) It highlights the entire row and not a range of cells (ie. A7:K1000)

Could anyone help me modify this?

Thanks