If its an Visualforce page simply write:

<span> {!Account__r.Name} <br/> {!Account__r.BillingAddress} </span>

I doubt Account__r.BillingAddress may create error for you. Let me know. You can also try

<span> {!Account__r.Name} <br/> <apex:outputText> value="{!Account__r.BillingAddress}"/> </span>

If it's a Visualforce page simply write:

<span> {!Account__r.Name} <br/> {!Account__r.BillingAddress} </span>

I doubt Account__r.BillingAddress may create error for you. Let me know. You can also try

<span> {!Account__r.Name} <br/> <apex:outputText> value="{!Account__r.BillingAddress}"/> </span>