How to extend the partition size in ubuntu

hi when i was installing ubuntu 14.04 that time i had windows 7 in my laptop and in the installing options i select "replece windows7 with ubuntu " although i thought it would remove only windows 7 files not any other partitions but it had deleted all partitions data

  1. is there any software to get back the data which was already deleted
  2. by default i have come up with / parition size is 450 Gb
  3. im unable to create a partitions in that 450Gb
    tell me how to create partitions

plesse tell me how to solve this issue without installing the ubuntu again


You can recover the date by using some recovery tools EaseUS Data Recovery

but for partitioning the disks just fallow the below link