Pink would be a great color for you to wear in the spring - you might even find something on sale now -
You should look for a fairly modest sheath or skater dress, nothing too short, tight or that has cutouts. It's a church occasion and everyone's eyes should be on the bride, not you...it's hard to find something nice, because there are so many kind of sleazy dresses - but hopefully here are a few possibilities:
http://www1.macys.com/shop/product/maison-jules-flutter-sleeve-crew-neck-dress?ID=1714685&CategoryID=18109&LinkType=#fn=COLOR%3DPink%26DRESS_OCCASION%3DParty%26sp%3D1%26spc%3D17%26ruleId%3D%26slotId%3D16
http://www1.macys.com/shop/product/maison-jules-metallic-dot-print-dress?ID=1714687&CategoryID=18109&LinkType=&swatchColor=Georgia%20Peach%20Combo%20Peach%20Combo%20Peach%20Combo#fn=COLOR%3DPink%26DRESS_OCCASION%3DParty%26sp%3D1%26spc%3D17%26ruleId%3D%26slotId%3D15
http://www1.macys.com/shop/product/maison-jules-sleeveless-dot-print-flared-dress?ID=1761524&CategoryID=5449&zone=PDP_ZONE_A&choiceId=cidA40011-b7909175-f3cd-486d-b533-8e22c4f4211c@H7@Customers%20Also%20Shopped$5449$1761524&LinkType=PDPZ1_Pos3
http://shop.nordstrom.com/s/bb-dakota-renley-lace-fit-flare-dress-nordstrom-exclusive/3524970?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=PINK+SHELL&resultback=346&cm_sp=personalizedsort-_-browseresults-_-1_1_B
These are beautiful, but more expensive:
http://shop.nordstrom.com/s/eliza-j-cap-sleeve-crepe-fit-flare-dress/3903682?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=&resultback=6380&cm_sp=personalizedsort-_-browseresults-_-1_17_D
http://shop.nordstrom.com/s/tahari-jacquard-sheath-dress/3905742?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=&resultback=6773&cm_sp=personalizedsort-_-browseresults-_-1_18_C
http://shop.nordstrom.com/s/adrianna-papell-lace-fit-flare-dress-regular-petite/3824780?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=LIGHT+DOVE&resultback=8039&cm_sp=personalizedsort-_-browseresults-_-1_21_B
http://shop.nordstrom.com/s/alfred-sung-boatneck-sheath-dress/3554994?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=PAPAYA&resultback=3455&cm_sp=personalizedsort-_-browseresults-_-1_10_A
http://shop.nordstrom.com/s/donna-morgan-jessie-twist-silk-chiffon-dress-regular-plus/3131802?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=BLUSH&resultback=5572&cm_sp=personalizedsort-_-browseresults-_-1_15_B
http://shop.nordstrom.com/s/donna-morgan-rhea-one-shoulder-chiffon-dress-regular-plus/3362496?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=BLUSH&resultback=2500&cm_sp=personalizedsort-_-browseresults-_-1_7_D