Leaking radiator ??

Hello fellow bikers.
I purchased my first 990 in december and only had a couple of runs and love it allready(i cought the KTM bug).
as i fired it up yesterday i noticed that there were some small dump/drying patches on the radiatore which in turn turned white (like tap water on washing machines heating element) and the coolant looks to be of water colour. Now i have never seen uncoloured coolant (pink or green usually) and the expansion tank is on minimum.

is this a common issue that KTM sd of 2006 reg has on radiatores chipped by road stones and do they come with a certain coolant colour.
im a bit worried that the previous owner has used just neat water which in turn would have buitl up a lot of gunch in the cooling system.

so my opptions are, get some radweld and change the water once sealed up with an appropriate coolant (not sure what make, grade to get).
or look for a new radiator on ebay and change it.

The latter is my prefered option but i desperately need to save some dosh for insruance and a new rear tyre and a service (oil very black).
so im thinking someone would have done a similar short term bosh job and hade some safe solution for me.
Nick

Hi bigash, what colour is your coolant? And I don't see wet patches on the floor but every time I start the bike I see a couple damp patches on the rad. I'm hopping is just condensation. I also discovered I get some exhaust leak at the last joint before the mufler (near the foot break) and I think it causes a lot of back fire. Do you know how to reseal it.
Nick