Definitely work on the recall, but yes, you need something to maintain distance control in the meantime. You can use a flexi-lead, but if you do, I would advise investing in a harness as well, as flexi-leads can cause horrible neck/back injuries in dogs if they pelt to the end and then suddenly get jarred back.
An alternative is a long line (also attached to a harness). You can buy specific dog-training long-lines, but horse lunge lines are just as good.
As for the recall training. My boy has always had a good recall - until now. When we lost our old girl back in April he suddenly decided that he would stop recalling to encourage me to play with him, as he's so bored without his friend to chase him around. I've done a lot of work with him since and his recall is great now - as long as he doesn't have a ball in his mouth. 
So, I have recently bought and can recommend, Total Recall which is a really good book for both setting the groundwork for good recall with a pup or new dog and also retraining dogs who have poor recall. It also discusses the specific problems with dogs such and scent and sighthounds (mines a sighthound 
, for whom recall training is often, er ... more challenging.
It's uses totally positive training methods and is a step by step plan, that's really easy to follow. You start all the training indoors, at home and gradually work your way up to taking it outside, then further afield, so you will still need some sort of distance control in the meantime.