Excel 2007 : Calculation on the basis of IF

Can anyone pls assit me on it. It would be most appreciated.

In excel i have to calculate gross weight..gross weight is "net weight+tare weight".
The net weight of a bag could be 50 lb or 25 kg..however the tare weight is always 0.3 kg..if the unit is "kgs" then its obvious that this is 25 kg per bag, and if its "lbs" then for sure its 50 lb per bags.
One more thing, if the code is "rtc" or "ipi" then the conversion from kg to lb will be "2.205", however if the code is other then these two, conversion will always be "2.2"


S. No. | Code | No. Of Bags | Unit | Net Weight | Gross Weight

1--------PPI--------800--------KGS--------20000-------- __________
2--------PPI--------800--------LBS--------20000-------- __________
3--------RTC--------800--------KGS--------20000-------- __________
4--------RTC--------800--------LBS--------20000--------__________
5--------IPI--------800--------KGS--------20000--------__________
6--------IPI--------800--------KGS--------20000--------__________
7--------SOM--------800--------KGS--------20000--------__________
8--------SOM--------800--------KGS--------20000--------__________
9--------BNS--------800--------KGS--------20000--------__________
10--------BNS--------800--------KGS--------20000--------__________

many thanks in advance!