Please help.

I want to evalue the returns of a series of investments as shown below.
2008 2009 2010 TOTAL IR = 0.05
INCR Sales $166,873 $813,114 $1,266,398 $2,246,385
Invest. $(105,500) $(164,150) $(170,609) $(440,259)
TOTAL $61,373 $648,964 $1,095,790 $1,806,126

I'm not sure if I should use NPV, IRR or PV. When I use the formula I also
have problems understanding the results.

Looking forward to your suggestions.

FA