PCR from cDNA library

[parin]

            I'm trying to do PCR from cDNA library but I got a low yield.
The size of PCR product is about 1.7 kb. I used 10 ul of cDNA library as a  
template in 50 ul reaction and used the extension time at 72 C about 3  
min. By doing that I got very low yield. Any suggestion to improve the  
yield would be appreciated.
                                          Thank you in advance
                                           Parin  Chaivisuthangkura
                                           Dept. of Molec & cell biol
                                            U. of Connecticut