You need to do two things 1. Separate the peptides from the proteins 2. Separate the peptides from each other. It would help if we new more about the sample in general terms (volume, what you expect to be in there, how much non-protein material like organic compounds etc.)

1. You can probably use agarose as substitute for sepharose. The size purification does not need to be very good, just enough to separate the proteins from the peptides. Almost any sepharose column will work, you should be able to borrow either the column or the media in most places. Depending on the volume a Centricon with a 10Kda cutoff may also be sufficient.

2. The standard way of purifying one peptide from other peptides is regular reverse phase HPLC with a C18 column. These columns are quite common, so if you can find an HPLC you should be ok.

3. You may need to use an ion exchange step (column material for this is cheap) to further purify the peptides from each other or other organic compounds