I'm trying to research the best way

 1st off have you checked ADSL is available where your house is located? Even if it is, what service would you be getting? Might be better to say what the problem is with the dongle, what is it? There are a number of WIFI companies around that likely match any ADSL, other than in big cities here in Italy...

Where you are down as living I doubt you have ADSL and even if you did I doubt it would be very good. A quick search for wifi Sarnano indicates there is a lot of local connectivity going on for hotspots for hotels etc, so I would guess it's a remote poor reception area. The dongles you have are a slow speed by today's standards (7.2Mbs is the lowest these days, with 42 the newest and highest), irrelevant if your reception is no good, but if only erratic, then a new dongle or better still MIFI unit would pay off. Then again if you are getting HSDPA (or UMTS) then you should have your dongle set to only connect to this - get back if you need help to check do so. Whatever you do with this type of access do not assume it does not work until you have tried it for an adequate length of time, it can take some time to settle.Not trying to put you off ADSL as I would go for this in the UK at the drop of a hat, just here in Italy I in fact think it has no  future (also in time the same for the UK). Where you are, if you could get it, it would probably end up a total waste of money and a difficult contract to get out of... Ideally there will be a WIFI company like WIMAX (they do not cover you area) that supply access by having lots of repeaters around to get good coverage. It may be there is such near you, but they are small and have not come up in my search, perhaps your neighbours have access or visit the Comune as they seem to be involved in gaining access for businesses in your area.