s3 instrument cluster/temp symbol

hi all jst joined forum find it very useful i hav an s3 1999,problem is instrument cluster has lines through it and temp symbol displays sometimes dnt kno whether fault is real or not temp indicator goes up to 90c sometimes but back down to 70 normally,anyone kno my problem,also anyone wher i would get genuine instrument cluster cheap as price in ireland is expensive,help would be greatly appreciated,thanks