Hi Celtic, Could you perhaps use a telephone answering service? There are a few around and they can handle your inbound calls. Sure this won't solve the problem of manning the shop but it could be a low cost way to at least have the phone answered. I think this service can be had from around €100 upwards.
In terms of keeping the shop open and meeting clients you are going to have to modify your opening hours and try and juggle both if you can't afford any hired help.