Although the sorcerer in your party may be casting GMW and Haste, your bard should still take those spells if he can. It's my opinion that certain spells are like disk space and money: You can't have too much.
Assuming all the other bases in your party are covered (you're playing a bard so they ought to be), an extra GMW or Haste now and again will only make the group's life much easier. If you have five party members, then you will need probably three to four castings of those (single target) spells per day depending on how powerful your magic weapons are and how many of your party fights with weapons. You'll need two (bow and arrows), the fighter will need one, and the cleric may need one too. Though the cleric can cast GMW too, freeing up cleric spells by having someone else do it is a good idea, especially when you need that extra Cure Critical Wounds to survive.