Will 525cc silicone unders fill my skin and give me braless cleavage? Measure 13cm. Removed old implants 9 months ago

Thank you for the question and picture. Based on your photograph,  you seem to have significant breast asymmetry and some breast ptosis present; you will likely benefit from  breast augmentation/lifting surgery.  Breast augmentation alone will not achieve an outcome that you will be pleased with long-term, when it comes to breast position on your chest wall and/or breast symmetry. My best advice: select your plastic surgeon carefully. Make sure that he/she has significant experience achieving the types of outcomes you will be pleased with. Then, communicate your goals carefully as well.  Working together you will come up with a good plan to achieve your goals. Generally speaking, the best online advice I can give to ladies who are considering breast augmentation/lifting surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. ***Ask to see lots of examples of his/her work. 
2. Again, have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining which operation and/or breast implant size/type/profile will most likely help achieve your goals. In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful.  For example, I have found that the use of words such as “natural” or "C or D cup" etc means different things to different people and therefore prove unhelpful. Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate. The use of computer imaging may be very helpful during this communication phase.
3. Once you feel you have communicated your goals clearly, allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals. Again, in my practice, this decision is usually made during surgery. The use of temporary intraoperative sizers with the patient in the upright position makes selection of the best breast implant size/profile relatively easy.
I hope this, and the attached link, helps. Best wishes. 

Thank you for your question. Unfortunately you will not be able to achieve your desired look with implants alone.  Based only on your picture you would probably need a breast lift. In addition you might require fat grafting or scar release from the previous incision around the areola. Good luck.