Gunners legend Parlour reckons his old side simply HAVE to keep the free-scoring Dutchman at the Emirates.And he insists Arsene Wenger should pay whatever it takes to ensure Van Persie, 28, commits his long-term future to the club.Van Persie sits atop the Premier League scoring charts with an incredible 25 goals already this season.But he is out of contract in June 2013 and has so far refused to discuss terms over a new deal.Arsenal boss Wenger is prepared to let Van Persie run his contract down but Parlour reckons there is no chance the club's board will allow him to leave for free.Parlour, who won three Premier League titles with Arsenal, said: "For me, the biggest signing they can make this summer is Robin van Persie."He's in a very strong position with one year left on his contract. Arsenal can't afford to let him go on a free transfer, so they couldn't keep him for a season."He'd be a massive loss if he left but if he doesn't sign a new deal this summer, they'll have to make a decision to sell him."Arsenal have agreed an £11million fee with Cologne which will see German star Lukas Podolski join the club this summer as Wenger looks to beef up his attacking options.But after losing Samir Nasri and Cesc Fabregas last summer for big money, Gunners fans are worried that Podolski is being lined up as a replacement for Van Persie — rather than a partner for him.Parlour added: "For me, you need both of them."If you want to challenge the likes of Manchester United and Manchester City you need quality strikers. If they can keep both of them, it could be vital."They ran out of steam against AC Milan in the Champions League and they didn't have the impact players on the bench."Marouane Chamakh and Chu-Young Park — are they good enough to play on a regular basis?"Podolski's experienced but not too old. At 26, you're in the prime of your career. He's played in big games."It's an opportunity for him to come to the Premier League and really turn it on next season."But Parlour has urged Wenger to spend BIG on a host of new recruits in order to boost Arsenal's chances of success next season.He reckons the North Londoners are in need of "four or five" new players and earmarked a replacement for Andrey Arshavin and a new defender as priorities.But with Jack Wilshere expected to return from injury soon and the emergence of teenage star Alex Oxlade-Chamberlain, Parlour predicts a bright future for his old club.He said: "It's exciting. With Wilshere coming back and four or five players added in the summer as well, it could be a really good season for Arsenal next year."Oxlade-Chamberlain has been an absolute revelation for Arsenal."Next season will be tougher but he's a great young player and I would play him in centre-midfield."He's a bit different to Wilshere and Aaron Ramsey so that nucleus of youngsters is very important to Arsenal's future."I would take him to the Euros. I was surprised he wasn't in the last England squad against Holland."It's good to bed these players in now so in the World Cup 2014, he would be used to being an England player. I would definitely put him in now."