The biovizBase package has a GRanges of the hg19 cytogenetic bands, so you could use that. There is also a GRanges with gene symbols in that package which makes it super convenient. Let's say we want the cytoband for BRCA2:
> subsetByOverlaps(hg19IdeogramCyto, genesymbol["BRCA2",])
GRanges object with 1 range and 2 metadata columns:
seqnames ranges strand | name gieStain
<Rle> <IRanges> <Rle> | <factor> <factor>
 chr13 [32200000, 34000000] * | q13.1 gpos50
seqinfo: 24 sequences from an unspecified genome; no seqlengths
So BRCA2 is in 13q13.1. Is that what you are after?