o leary agrees new villa contract aston villa boss david o leary signed a three-and-a-half year contract extension on thursday  securing his future at the club until summer 2008.  o leary s future was in question  but villa chairman doug ellis said he was happy to secure the deal.  david s record since his arrival in 2003 is excellent and he shares the board s amibitions in taking this club forward   he told villa s website.  for this reason it was important we got this right.  o leary put pen to paper after deals were sorted for his right-hand men roy aitken and steve mcgregor.  it was important to me roy and steve  an integral part of my team  should stay for the same time   o leary said on thursday ahead of signing his new deal.  someone has to try and put aston villa back where they should belong and i m up for the challenge. earlier in december  there were rumours o leary would quit if he is not offered a new deal before the end of the season.  but he denied that  saying he was happy to take on the challenge of improving villa s fortunes in the long term.  i want to make sure by the end of the five years i would have been in charge that villa are achieving top six finishes in the premiership on a regular basis   said o leary  who took over at villa park in may 2003.  but to achieve that  and take the next step forward  we do need to bring in quality players.  i would like a couple next month if at all possible to set us on the way.  meanwhile  o leary has rapped skipper olof mellberg for his comments before sunday s derby with birmingham.  mellberg spoke of his dislike of villa s rivals ahead of the match  which steve bruce s side won 2-1.  i ve had more than a quiet word with olof. it s been said within the whole group  not as a one-to-one   he told villa s website.  you shouldn t leave yourself open to be shot down. you shouldn t give people the chance to take cheap shots at you and he set himself up for that.