Para añadir a tu blog uno de estos botones de Google plus +1 tiene que ir a :
Si usas la interfaz antigua entra en Diseño | Elementos de la página | Añadir gadget | HTML/Javascript.
Si usas la nueva interfaz entra en Diseño | Añadir gadget | HTML/Javascript. y pega el codigo del boton que tu quieras.
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh4.googleusercontent.com/-xckKK57B5SQ/Ts0W2Lyu38I/AAAAAAAAAhE/G418dY5hirQ/s100/google1.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh6.googleusercontent.com/-VyJhxp5xI14/Ts0W2cI7ViI/AAAAAAAAAhM/P2vxOVUJIZU/s100/google2.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh5.googleusercontent.com/-vLLZLsW7Mjg/Ts0W2ljN3MI/AAAAAAAAAhQ/65ciE0B2eT8/s100/google3.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh3.googleusercontent.com/-21eQkgMPB5A/Ts0W2wQOgMI/AAAAAAAAAhc/eLa9x-AOpwo/s100/google4.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh4.googleusercontent.com/-0v1FgcoZvR0/Ts0W3cTJGvI/AAAAAAAAAhs/RVm6RWZfuGc/s100/google5.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh6.googleusercontent.com/-ceT7pXQPoHc/Ts0W3PyQcYI/AAAAAAAAAhk/pchKQJBx2Z0/s100/google6.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh3.googleusercontent.com/-AT_6V-GTZMU/Ts0W3hbXN8I/AAAAAAAAAhw/-UrzlxqaVAY/s100/google7.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh3.googleusercontent.com/-AT_6V-GTZMU/Ts0W3hbXN8I/AAAAAAAAAhw/-UrzlxqaVAY/s100/google8.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh5.googleusercontent.com/-zMsfJ6y1ebU/Ts0W4Jf_cGI/AAAAAAAAAiE/xWWAD7CLpYA/s100/google9.png" /></a>
<a style="" href="URL DE TU GOOGLE+"><img src="https://lh6.googleusercontent.com/-fw6KqcxlKYE/Ts0W4ACI86I/AAAAAAAAAiI/t2ZquRjArBY/s100/google10.png" /></a>
