http://www.savingfortravel.com/round-the-world-budget-calculator-step-2.php

Peru 40 week(s) £4480
India 4 week(s) £392
Nepal 3 week(s) £273
Malaysia 3 week(s) £336
Laos 3 week(s) £294
Thailand 3 week(s) £378
Peru 2 week(s) £224
Argentina 2 week(s) £252
Brazil 2 week(s) £294
Bolivia 2 week(s) £210
Honduras 3 week(s) £315
Costa Rica 3 week(s) £357
Panama 3 week(s) £378
Belize 3 week(s) £378
Guatemala 3 week(s) £315

Round the World ticket (average cost): £1250
Travel Insurance (approx. cost for 79 weeks): £455
Estimate for budget: £10581

15,520.90 USD