Hi, I have a file with this format (hg19 human genome)

#Chr    Start   End Ref Alt
1   12673   12673   G   A
1   12719   12719   G   C
1   12783   12783   G   A
1   12807   12807   C   T
1   12839   12839   G   C
1   12882   12882   C   G
1   13012   13012   G   A
1   13079   13079   C   G
1   13110   13110   G   A

I don't have the gene names in the file, I want to use the 1st 3 columns of the files (col1 #chr, col2 #Start, col3#End)and want to add gene names. Any tools or programs to do that from GTF, bed or ref fasta of hg19. Need help

Thanks for the help.