If else Statement in Swift

I'm a newbie at swift, so how do I add an extra else if statement saying greater than 56 & less than 65 to my button?

The button work fine, it just need one more additional statement added to finished up my coding.

@IBAction func Submit4Button(sender: AnyObject) {

        let a: Float? = (EnterH4Dimension.text as NSString).floatValue

        if a > 65 {

            self.DimensionLabel.text = " Cameron H4 With Guide Pins."

            yesButton.hidden = false
            noButton.hidden = false

            emailButton.hidden = true
            DimensionLabel.hidden = false

            self.view.endEditing(true)

        }

        else if EnterH4Dimension.text == "" {

            noButton.hidden =  true
            yesButton.hidden = true

            var alert = UIAlertController(title: "Dimension", message: "Missing Data Input.", preferredStyle: UIAlertControllerStyle.Alert)

            alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))

            self.presentViewController(alert, animated: true, completion: nil)

        }

        else {

            self.DimensionLabel.text = "Dimensions meet guideline"

            noButton.hidden =  true
            yesButton.hidden = true

            DimensionLabel.hidden = false
            shallowDimButton.hidden = true
            emailButton.hidden = false
            self.view.endEditing(true)

        }

    }