I will "assume" you have the reprise faucets with a 2-way diverter valve (also available with 3-way valve or diverter spout). Next give porcher a call at 1-800-359-3261 and tell them the model number of your faucet if possible and your situation. If the faucets are only 2 months old they should send out a diverter repair kit free of charge, i'm not familiar with porcher's warranty.
Then if you purchased the faucets and installation from a plumbing company, give them a call and ask about your warranty coverage of the fixtures they installed. They may come out and fix it for free, but most likely will charge labor. The repair kit is simple to install if you want to give it a try yourself.
EDIT: just noticed you said "Old House".... If you have galvanized pipe for water distribution you will most likely have problems with your faucets, paticularly the newer style faucets, until the galvanized is replaced. The newer cartridge style faucets just can't handle the rust particles and sediment, you can't just turn the handle a little tighter to shut them off like the you can with the old compression style faucets.